Clephas

On another note, I love wunderwaffels.  I just also enjoy stories where there is no wunderwaffel.  I'm an isekai junkie in general... though it is a huge letdown when a real action story that is serious has a protagonist who is too overpowered for there to even be a struggle or strife.  It's one thing if he ends up that way towards the end (like with Hajime in Arifureta Shokugyou), but most attempts to do serious plots and action with an op protagonist tend to fall apart near the end.  The exception is when the main antagonist is just as op as the protagonist.

I went for Sakura, Moyu, personally.  

Komorebi no Nostalgica.

Natsuiro Kokoro Log is yet another low-quality charage not worth mentioning except to diss it.
Tarareba is a halfway decent charage by Aries, a company that generally doesn't produce high-quality games in the first place.
By now, a lot of you already no Sakura no Mori Dreamers.  However, I'll note that this was one of several horror mystery series that came out in this and the next year that were halfway decent.  If you liked Sakura no Mori, I suggest playing Butterfly Seeker.
Soshite Hatsukoi ga Imouto ni Naru... is a top class nakige that somehow - yet again - came out of a low-budget subsidiary of Alcot.  This game, like most of Alcot Honey Comb's games, is pretty reliant on the writer quality in comparison to most modern VNs, which tend to be reliant on visual quality to pass themselves off as being worth the money.  This game made me cry at least a half-dozen times each time I played it, because it was just that good.  

Angel Magister-  This one tried too hard to mix SOL with plotge, and as a result it didn't really fulfill on either side.  It wasn't horrifically bad, but it isn't great either.
Kitto Sumiwataru Asairo Yori mo- Shumon Yuu.  I don't need to say anything else.  All games by Shumon Yuu are automatically awesome.
Natsuyume Nagisa- One of the games Saga Planets became known for, a solid nakige with a mild mindfuck.
Mecha-mimi- A decent android love story plotge pretending to be a charage on the surface.
Sevens- Straight-out moege/charage from the era in which that was 90% of what Whirlpool did.
Kurenai no Tsuki- A great inaka fantasy mystery based in fall (easily the best setting for that kind of thing).  I found this one enjoyable both times I played it.  Best heroine is the hidden one though, lol.

I thought about trying to explain the reasons... but they tend to vary from person to person.  Some enjoy it because it makes them feel like they are better/more able than others, others purely like adding new vocabulary and grammar usage to their repertoire, and yet others just enjoy the magic of what can be done with languages if you are creative enough.  To be blunt, I'm more of the last one at this point... early on, it was more a bit of reason one and two though.  Nowadays, I've  just gotten to the point where an interesting set of lines is enough to make me feel happy, which I know sounds weird.
To be blunt, Japanese is a much, much more flexible language than English... at least American English, anyway.  The Japanese language never quite abandoned indirectness, which is seen as dishonest by many English speakers.  It is also one of the prime reasons why it is so difficult to translate Japanese to English and why I can still find new things to learn by replaying games like this over and over.  Americans habitually avoid indirect language outside of trained creative writing and politics, and anyone seen using it is seen as smarmy or dishonest (unless you agree with them, of course, lol).  
Implied subjects, layered meanings, colloquialisms, etc etc... I can always find something new if I look hard enough in games like this.

My first Gundam was Wing... but my first mecha was Voltron.

Story-wise, the original Nier is an excellent game.  While the gameplay suffers from the usual issues with camera angles that were endemic to most of the ps2 and ps3 era action-jrpgs, it was more than solid enough for a solo title more focused on plot than gameplay.  
Despite the somewhat iffy nature of English dubs, I found Nier's cast to be superlative.  The titular protagonist, Nier was a man with a very clear-cut motive and a powerful driving personality that was constantly razor-focused on his daughter's well-being and, later, that of his friends and companions.
Kaine, the game's sole heroine, is a foul-mouthed girl possessed by an insane serial-killer Shadow.  Throughout much of the game, her role is to kick characters' butts when they start to brood, but, depending on the ending you get, her role changes drastically.  Like many such characters with dark personalities and foul mouths in jrpgs, she has a heart of gold (though it is really, really hidden outside of specific moments).
Emil, the sole character seen in both Nier games, is a young man in the original game, suffering from blindness and from numerous other issues.  He is the most innocent of the characters, with the possible exception of the oft-missing Yona, serving as a strong contrast to the somewhat antagonistic relationship between Nier, Grimoire Weiss, and Kaine.
 

lol, don't spoil it for the newbies.  We want to make them buy Drakengard and Drakengard 3, after all.
 
 

In terms of books I sampled (read the first ten chapters at least) the number balloons to 300 or so... the seventy I'm talking about are the ones I was finding the most interesting.  Here is a list of the ones I enjoyed the most (even if some were trashy).
The Chaos Seeds (think an isekai/other world story with a protagonist who constantly swings back and forth between enlightened self-interest, pragmatism, and lust for power/stat geeking).
The Stork Tower (extremely interesting dystopian future with a genius street rat who makes powerful enemies in the virtual and real worlds)
Light Online (protagonist starts out as an out-of-luck NEET who is about to be turned into a virtual slave and then manages to rise high by playing a VRMMO in an unusual style).
The Ten Realms - Protagonists are an amputee mercenary named Erik and his comrade and best friend Rugrat.  They end up in the Ten Realms, two soldiers in a land of magic, and they quickly realize the only way to be themselves is to gain power and challenge themselves.  Sort of a blend of Wuxia cultivation, military fantasy, and craft obsessive nation-building with two foul-mouthed soldiers with hidden depths leading the way.
The Dark Elf Chronicles- In a future where a 'zombie particle' has contaminated most of the lifeforms on Earth, a few survivors try to live long enough to find a way to copy themselves into an online game while also stabilizing said game so it won't be a pure hellworld when they do so.  Tons of ups and downs in this story.
The Shadow Sun series- In this one, a mysterious System essentially unleashes massive numbers of super-powered monsters to cull humanity in preparation for aliens bidding on the land and resources.  Very much a survival apocalypse story for the first three books.  
The Silver Fox & the Western Hero - Pure Wuxia with hardcore cultivation and horrid levels of racial prejudice... and a young former American plopped down in the middle who has a stat sheet in his head.  The protagonist seems fairly normal, until he isn't.  He is intelligent to the point of being brilliant, and absolutely devoted to the path he chooses.  However, he is also capable of rising above his own desires at key points.  Honestly, I can't wait until the next one comes out.
Battleborne-  First in a new series about a soldier who dies with his unit and gets reincarnated as a combination of several races by a Valkyrie as reward for his life of war and bravery.
All Trades- A former conman goes into a virtual reality game to earn the money to give back to the family that supported him after his term in prison.  He really has turned a new leaf, but he quickly finds himself riding the figurative tiger by the tail as he tries to do right by those around him while also earning enough money to pay off his loan shark.

So does Richter.
Overall, you have to be primed somewhat to really get into the genre.  As far as I can determine, there are a number of qualities that benefit anyone trying out the litrpg genre.
1.  Being familiar with and enjoying stat-based rpgs.
2.  Being something of a stat/skill geek
3.  being able to suspend disbelief sufficiently to dive into a world that feels somewhat artificial due to the presence of stats and obviously quantified growth.
For me, the recent growth of a similar genre in anime is what made it easy.  

Grisaia... ah Grisaia...
Sorry, couldn't resist.
People often try to present the series as something completely unique... and there are some elements to the series that stand out.  However, these elements were all drawn from earlier VNs in one way or another.
School for exiled rich kids and problem children: Haruka ni Aogi, Uruwashi no anyone?
Protagonist is a deeply mentally scarred individual who lacks common sense:  Akatsuki no Goei anyone? (also Full Metal Panic, as Sagara and Yuuji have so many common threads it made me seriously laugh my ass off at the time)
Incestuously mutually dependent relationships between siblings:  So many VNs it isn't even funny.
Heroines with extreme emotional disabilities and traumas:  Again, numerous games, even before Grisaia came out
Twisted relationship with a heroine that began with a near-parental bond: Haruka ni Aogi, Uruwashi no (again)
The list goes on... but I'm going to come right and say this.
Just because it isn't perfectly unique doesn't mean it isn't good.  I will go farther in saying that anyone who is playing Grisaia in English is missing out, because what is said is often less important than what isn't said (the comedy aside), and English sucks at that kind of thing.
Now for second and third game... I seriously bashed the second game for being a repeat of Akagoei's second game, as both of them end after blasting you with the protagonist's past, though Grisaia took it a step further by making it a cliffhanger (which was horrible, since I had to wait a year or so to see the rest).   Getting to know Yuuji's past was great, since the limited bits and pieces that are dropped as hints or comments in Amane's  path aren't enough to give you a good idea of how Yuuji lived until now.
The third game is basically one solid storyline to the end, which is its primary draw and the one area where it completely trumps the original game, which was SOL heavy in comparison.  The fact that it was a harem ending didn't bother me... I love harem endings, regardless of genre.  My problem was with Michiru's standing in that ending, lol (Michiru being my least liked heroine of the original... no make that I just actively disliked her).  
I did think that it channeled a little too much of the 'unify the original game's paths' drama into a single comprehensive story thread' idea.  It reminded me of what a lot of early anime made from visual novels did, where all the heroines paths were sort of mashed together in the anime in an attempt to accelerate the story, often with mixed results.  
With VNs, due to most of them being multipath, sequels rarely work out in a way that isn't awkward, and Grisaia is not an exception to this rule.  I love Grisaia, but that doesn't mean it is lacking in flaws. 

Just finished the Stork Tower novels that have come out so far... more cliffhangers.  I love Atherleah, but the way things keep expanding reminds me of a lot of sci-fi series that collapsed toward the later books because they couldn't keep track of all the balls in the air.  Atherleah has some of the best qualities of a fantasy or sci-fi protagonist in a litrpg: a firm set of ethics, if not morals; the cleverness or intelligence to think outside of the box and challenge the system; and a personal goal that never quite gets lost in the constant deluge of events.  
I just wish the author had organized this into arcs instead of just making things endlessly complex.  The way Leah runs on a near-24/7 schedule due to future science makes me wince in sympathy regularly, and her schedule just keeps getting more packed.

In terms of books I sampled (read the first ten chapters at least) the number balloons to 300 or so... the seventy I'm talking about are the ones I was finding the most interesting.  Here is a list of the ones I enjoyed the most (even if some were trashy).
The Chaos Seeds (think an isekai/other world story with a protagonist who constantly swings back and forth between enlightened self-interest, pragmatism, and lust for power/stat geeking).
The Stork Tower (extremely interesting dystopian future with a genius street rat who makes powerful enemies in the virtual and real worlds)
Light Online (protagonist starts out as an out-of-luck NEET who is about to be turned into a virtual slave and then manages to rise high by playing a VRMMO in an unusual style).
The Ten Realms - Protagonists are an amputee mercenary named Erik and his comrade and best friend Rugrat.  They end up in the Ten Realms, two soldiers in a land of magic, and they quickly realize the only way to be themselves is to gain power and challenge themselves.  Sort of a blend of Wuxia cultivation, military fantasy, and craft obsessive nation-building with two foul-mouthed soldiers with hidden depths leading the way.
The Dark Elf Chronicles- In a future where a 'zombie particle' has contaminated most of the lifeforms on Earth, a few survivors try to live long enough to find a way to copy themselves into an online game while also stabilizing said game so it won't be a pure hellworld when they do so.  Tons of ups and downs in this story.
The Shadow Sun series- In this one, a mysterious System essentially unleashes massive numbers of super-powered monsters to cull humanity in preparation for aliens bidding on the land and resources.  Very much a survival apocalypse story for the first three books.  
The Silver Fox & the Western Hero - Pure Wuxia with hardcore cultivation and horrid levels of racial prejudice... and a young former American plopped down in the middle who has a stat sheet in his head.  The protagonist seems fairly normal, until he isn't.  He is intelligent to the point of being brilliant, and absolutely devoted to the path he chooses.  However, he is also capable of rising above his own desires at key points.  Honestly, I can't wait until the next one comes out.
Battleborne-  First in a new series about a soldier who dies with his unit and gets reincarnated as a combination of several races by a Valkyrie as reward for his life of war and bravery.
All Trades- A former conman goes into a virtual reality game to earn the money to give back to the family that supported him after his term in prison.  He really has turned a new leaf, but he quickly finds himself riding the figurative tiger by the tail as he tries to do right by those around him while also earning enough money to pay off his loan shark.

In terms of books I sampled (read the first ten chapters at least) the number balloons to 300 or so... the seventy I'm talking about are the ones I was finding the most interesting.  Here is a list of the ones I enjoyed the most (even if some were trashy).
The Chaos Seeds (think an isekai/other world story with a protagonist who constantly swings back and forth between enlightened self-interest, pragmatism, and lust for power/stat geeking).
The Stork Tower (extremely interesting dystopian future with a genius street rat who makes powerful enemies in the virtual and real worlds)
Light Online (protagonist starts out as an out-of-luck NEET who is about to be turned into a virtual slave and then manages to rise high by playing a VRMMO in an unusual style).
The Ten Realms - Protagonists are an amputee mercenary named Erik and his comrade and best friend Rugrat.  They end up in the Ten Realms, two soldiers in a land of magic, and they quickly realize the only way to be themselves is to gain power and challenge themselves.  Sort of a blend of Wuxia cultivation, military fantasy, and craft obsessive nation-building with two foul-mouthed soldiers with hidden depths leading the way.
The Dark Elf Chronicles- In a future where a 'zombie particle' has contaminated most of the lifeforms on Earth, a few survivors try to live long enough to find a way to copy themselves into an online game while also stabilizing said game so it won't be a pure hellworld when they do so.  Tons of ups and downs in this story.
The Shadow Sun series- In this one, a mysterious System essentially unleashes massive numbers of super-powered monsters to cull humanity in preparation for aliens bidding on the land and resources.  Very much a survival apocalypse story for the first three books.  
The Silver Fox & the Western Hero - Pure Wuxia with hardcore cultivation and horrid levels of racial prejudice... and a young former American plopped down in the middle who has a stat sheet in his head.  The protagonist seems fairly normal, until he isn't.  He is intelligent to the point of being brilliant, and absolutely devoted to the path he chooses.  However, he is also capable of rising above his own desires at key points.  Honestly, I can't wait until the next one comes out.
Battleborne-  First in a new series about a soldier who dies with his unit and gets reincarnated as a combination of several races by a Valkyrie as reward for his life of war and bravery.
All Trades- A former conman goes into a virtual reality game to earn the money to give back to the family that supported him after his term in prison.  He really has turned a new leaf, but he quickly finds himself riding the figurative tiger by the tail as he tries to do right by those around him while also earning enough money to pay off his loan shark.

In terms of books I sampled (read the first ten chapters at least) the number balloons to 300 or so... the seventy I'm talking about are the ones I was finding the most interesting.  Here is a list of the ones I enjoyed the most (even if some were trashy).
The Chaos Seeds (think an isekai/other world story with a protagonist who constantly swings back and forth between enlightened self-interest, pragmatism, and lust for power/stat geeking).
The Stork Tower (extremely interesting dystopian future with a genius street rat who makes powerful enemies in the virtual and real worlds)
Light Online (protagonist starts out as an out-of-luck NEET who is about to be turned into a virtual slave and then manages to rise high by playing a VRMMO in an unusual style).
The Ten Realms - Protagonists are an amputee mercenary named Erik and his comrade and best friend Rugrat.  They end up in the Ten Realms, two soldiers in a land of magic, and they quickly realize the only way to be themselves is to gain power and challenge themselves.  Sort of a blend of Wuxia cultivation, military fantasy, and craft obsessive nation-building with two foul-mouthed soldiers with hidden depths leading the way.
The Dark Elf Chronicles- In a future where a 'zombie particle' has contaminated most of the lifeforms on Earth, a few survivors try to live long enough to find a way to copy themselves into an online game while also stabilizing said game so it won't be a pure hellworld when they do so.  Tons of ups and downs in this story.
The Shadow Sun series- In this one, a mysterious System essentially unleashes massive numbers of super-powered monsters to cull humanity in preparation for aliens bidding on the land and resources.  Very much a survival apocalypse story for the first three books.  
The Silver Fox & the Western Hero - Pure Wuxia with hardcore cultivation and horrid levels of racial prejudice... and a young former American plopped down in the middle who has a stat sheet in his head.  The protagonist seems fairly normal, until he isn't.  He is intelligent to the point of being brilliant, and absolutely devoted to the path he chooses.  However, he is also capable of rising above his own desires at key points.  Honestly, I can't wait until the next one comes out.
Battleborne-  First in a new series about a soldier who dies with his unit and gets reincarnated as a combination of several races by a Valkyrie as reward for his life of war and bravery.
All Trades- A former conman goes into a virtual reality game to earn the money to give back to the family that supported him after his term in prison.  He really has turned a new leaf, but he quickly finds himself riding the figurative tiger by the tail as he tries to do right by those around him while also earning enough money to pay off his loan shark.

I am a prolific abuser of ellipses myself.  I abuse them because... well, it is so easy to use them as a means of expression.  Emotion, humor, hesitation, etc.  These things can all be expressed in a wall of text to indicate the state of the writer's thoughts using an ellipses.
They are just so darned convenient.

Princess Frontier created one of AXL's signature styles, the high fantasy SOL VN.  They have since created a number of such games, all of which have been fun reads.  The funny thing is, no one else is doing this, which strikes me as odd sometimes when I let myself think about it.

Fortune Arterial was the game that came to be the base for the 'August Game Rules'.  
1) August games have good concepts, good protagonists (heroines tend to be hit and miss).
2) August will always make their games look pretty.
3) August will always fumble the execution for the last third of the game.
Tsuki to Majo to Taiyou to is a Silver Bullet game... that in itself says a lot, but I'll elaborate.  Silver Bullet games always make serious attempts to escape the mundane trends that were beginning to take over when they were formed, but they always fail, due to a lack of writing talent.  Poor Silver Bullet.  Their last three games were almost total disasters (I should know, since I played them) and Consome is the best game they've made... and it is still not something I would go out of my way to play now.  Hanafubuki and Kachou Fuugetsu (based in the same setting) are interesting games that nonetheless inevitably feel derivative, even if they are sometimes eerie in atmosphere.  Setsuei is one of those games that would satisfy the mild horror romance crowd and few others (ironically, this was one of their few games I felt escaped being mediocre in concept, if not execution).
 

One thing I've noticed about the best Japanese VN companies is that they manage to keep all elements of their VNs at a high level or at least an aesthetically pleasing level.  Visual elements are pleasing (though the Japanese baseline is much, much higher due to a near-standardization of the art quality in commercial vns, than the Western one), music direction is still a thing (you know, the thing that vanished after the PSX era from regular games, due to the arrival of voice acting), and voice-acting is even more refined (for the most part, though there are exceptions) than what you see in anime.  
The area where the Japanese stumble is writing.  Due to the 'crutch' of voiced dialogue, there is a tendency for many writers to try to tell most of the story with dialogue and sprite poses.  However, that is like using only black and white when you have a full color palette available.  If there was one thing that struck me immediately playing my first VNs, it was the sheer impact of combining first-class narration with the other elements of a visual novel (as well as coordinating those elements).  Heck, I've even encountered games where the appropriate use of music, narrative, and voices have carried the game past lower quality artwork to startling heights (Devils Devel Concept being a premier example) that only get better the more times you play it.  
When everything is high level, however, you wouldn't believe the degree to which it blows you away... the first time I played Dies Irae (In Japanese) it destroyed me completely.  Everything about it quite simply was so different from what I'd experienced previously, while using many of the same elements.  Bradyon Veda did something similar to me, as did Sakura, Moyu and Kitto, Sumiwataru Asairo yori mo,.  To put it simply, there are works out there that utilize the full 'palette' of what the medium is capable of.  However, I can tell you that very few companies would have the wherewithal to gather the talent that can create such games.  
First, writers with that kind of sheer brilliance are rare.  Second, companies that might gather such writers would not be able to handle them, because each one needs different things to work at 100%.  Third, maintaining all the other parts of a game (Art, VA, Music, and direction) at the same high level even if you have the writing staff has got to be a serious pain in the rear.  
To be blunt, Visual novels have a lot of moving parts, and just throwing extra people at it doesn't usually work (very few games with multiple main scenario writers or artists have turned out well, though assistants sometimes work out fine).  In retrospect, is is amazing that I can name double digits worth of games that have drawn on every element of the medium to its fullest, considering what a pain it must have been to put it all together.

One thing I've noticed about the best Japanese VN companies is that they manage to keep all elements of their VNs at a high level or at least an aesthetically pleasing level.  Visual elements are pleasing (though the Japanese baseline is much, much higher due to a near-standardization of the art quality in commercial vns, than the Western one), music direction is still a thing (you know, the thing that vanished after the PSX era from regular games, due to the arrival of voice acting), and voice-acting is even more refined (for the most part, though there are exceptions) than what you see in anime.  
The area where the Japanese stumble is writing.  Due to the 'crutch' of voiced dialogue, there is a tendency for many writers to try to tell most of the story with dialogue and sprite poses.  However, that is like using only black and white when you have a full color palette available.  If there was one thing that struck me immediately playing my first VNs, it was the sheer impact of combining first-class narration with the other elements of a visual novel (as well as coordinating those elements).  Heck, I've even encountered games where the appropriate use of music, narrative, and voices have carried the game past lower quality artwork to startling heights (Devils Devel Concept being a premier example) that only get better the more times you play it.  
When everything is high level, however, you wouldn't believe the degree to which it blows you away... the first time I played Dies Irae (In Japanese) it destroyed me completely.  Everything about it quite simply was so different from what I'd experienced previously, while using many of the same elements.  Bradyon Veda did something similar to me, as did Sakura, Moyu and Kitto, Sumiwataru Asairo yori mo,.  To put it simply, there are works out there that utilize the full 'palette' of what the medium is capable of.  However, I can tell you that very few companies would have the wherewithal to gather the talent that can create such games.  
First, writers with that kind of sheer brilliance are rare.  Second, companies that might gather such writers would not be able to handle them, because each one needs different things to work at 100%.  Third, maintaining all the other parts of a game (Art, VA, Music, and direction) at the same high level even if you have the writing staff has got to be a serious pain in the rear.  
To be blunt, Visual novels have a lot of moving parts, and just throwing extra people at it doesn't usually work (very few games with multiple main scenario writers or artists have turned out well, though assistants sometimes work out fine).  In retrospect, is is amazing that I can name double digits worth of games that have drawn on every element of the medium to its fullest, considering what a pain it must have been to put it all together.

I've mostly given up on anyone in Japan utilizing the medium properly.  The ones who do don't seem to prosper (Light for instance) or are entirely reliant on a single genius (Caramel Box, Propeller before it disbanded after two failures in a row without Higashide).  I think the reason for this is that the medium got defined really early on as an ero and romance focused medium, due to the twin dominance of the moege and nukige genres.  While there are a number of VNs out there that qualify as true literature, it takes someone with a lot of patience to find them in the first place.  
I don't have the knowledge to speak definitively about the Western market, however.
Edit: Part of the reason the Japanese market is so awful is that Japanese find it difficult to ignore preconceptions.  It took even longer than it did here for otakus to stop being treated as second-class citizens, and even now, that prejudice is pretty strong in some quarters (particularly the over-sixty generations).  This tendency to simply believe the preconceptions created by others' words and initial impressions have led to mostly people interested in ero and idealized romances to take an interest in consumer visual novels in Japan, meaning that a greater majority of the games are made to satisfy that type of consumer.  The market is currently contracting (yes it is contracting) and as a result, a disproportionate number of games escape the 'moege' label than in previous years.  However, this is simply because the makers who cater to people who want actual plots or something else in their visual novels still have about the same number of consumers, not because there are a great many more such in an absolute sense.  In time, this shift might result in more serious works gaining an advantage, but that is only if the moege/nukige genres don't bounce back.

Shugotate - One of the two series that gave life to a curiosity sub-genre, the trap protagonist.  In this case, it created the 'combat-capable trap protagonist in a plotge' sub-genre, which turned out to have a weird life of its own after this came out.  A complete remake recently came out, with mostly aesthetic upgrades, though I haven't really played it yet.  This game has all the elements you would expect of the genre, from the protagonist constantly worrying about getting caught while being disappointed no one realizes he is a man, as well as the comedy, characters, and writing of an AXL game.
Ouzoku- SofthouseChara's most famous game.  To be honest, this is one of those Rance-type games with a good story despite the fact that the protagonist is the worst kind of womanizer.  The gameplay is decent, but it is somewhat reminiscent of Langrisser, with the need to heavily budget-manage as well as put out units that can be effective on the individual battlefields you are deploying them to.  As such, it is not in any way suited for beginners to turn-based tactical gameplay.  It also doesn't have a decent tutorial to help you learn the ropes, so most people will end up restarting from the beginning after running out of money partway through.
ExE- Yuzusoft's first chuunige.  Actually, its only chuunige.  It is very much a representative of the early genre that was born with Tsukihime, with a school-going protagonist who suddenly begins to get powerful rather than having any skills of his own previously, a seemingly devious plot that the protagonist stumbles upon by accident that somehow has deep links to his tragic past, and heroines who mysteriously fall for him inside an hour of gameplay.  In other words, it is a decent game, but it has all the flaws of the early chuunige genre to annoy the experienced while probably being one of the easiest entryways for people new to untranslated to try the genre.

The Soleil series is all over the place in terms of quality and setting.  Part of this seems to be because Cthulhu Mythos mixes in at times, and because it is essentially a linked multiverse (unlinked multiverses being those like Type-Moon's Fate/Tsukihime series) where a near infinite number of versions of the post-Ragnarok world have come into existence.  Gouen no Soleil is pretty much 50% Cthulhu, 30% Norse, and 20% Taoist, whereas in other cases it only mixes in slightly.  However, every game in the series is a dark chuunige (I say dark, because most chuunige, especially modern ones, generally don't go as far as these games when it comes to the themes and bad endings).   
Shin Shirogane is not precisely an alternative version but rather a close sibling game.  Essentially, huge parts of the characters' roles, personalities, and origins get shattered and remixed with others, and this creates a much more chaotic and darker situation.  Honestly, I think it is the worst game in the series, because it was evident the writer couldn't decide what he wanted to do.
The chronological sequel to Shirogane is actually Soukyuu no Soleil, though I won't spoil it for you.
So far, the best game in the series is probably Gouen or Blade X Bullet.

Good choices of games all around...