Guide: I'm not sure I found everything, but I'll try to give some hints.
- Meeting someone on the train is affected only by the time you board the train and the car you get in.
- If you don't meet anyone on the train (or lose sight of them...), you can still meet someone in one of the four locations. The carried item affects what happens after you meet someone.
- It looks like there isn't any persistent state between plays. Meaning you don't necessarily need all hints, you could get lucky and get to an ending right away.
- I just made a 4x4x4x4 chart and searched it randomly then followed hints
Review:
凄いだよこのゲーム。The production values are very high. The English is good, better than in some Western visual novels. There is a nice sense of mystery. Not all of my questions about what the characters were talking about were answered by the end (but maybe I need to play more). This might be desirable in a mystery novel, I don't like VNs that make everything painfully obvious, but it can also be frustrating. I haven't played the Japanese version (yet?), but maybe it's a little obfuscated by the translation. While the grammar is correct, there might be some cultural context missing. When I was reading a dialogue, I had to scroll back sometimes to understand who said what.