I... I don't really know. I have never read I VN that I've really hated, but "worst" it is, so I have to go with this one.
It was probably the first VN I've ever read, despite never even knowing what a VN was at that particular time (so I don't count is as my first VN).
For some weird reason, I still have it on my computer after this entire time, so recently, I sat down to actually try to go through it...
Since I'm not a fan of nukiges (I think that It might be only nukige I have ever played, in fact), it was just tedious to go through. There was only one route that I could get some enjoyment of, and that was the one with the fewest H-scenes, but it was also the one that at least felt romantic in nature... (again, I don't read nukige, and I'm quite sure that there are much, MUCH worse ones out there)