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It covers the overall story of the VNs, yes. There is no continuation after. (I won’t count phantom bullet or whatever as canon, fight me.) Kajitsu is extremely different in places, though, especially the endings. (The anime ending to Kajitsu is anime original and not a part of the VN.) So I’d recommend reading Kajitsu. The other two are pretty well adapted. (And in my opinion those two VNs aren’t that interesting anyways.)