Yume 2kki is a very hard game to describe. It's one that's captivated my time for far longer than I care to admit despite its lack of any real narrative. My only real complaints about this game go down to having to use the wiki to get to any of the interesting parts, and the hunt for wallpapers that takes up much of the gameplay after collecting every Effect sometimes getting annoying. I also feel that it's rather bloated with content, mostly because of the collaborative nature of the project. Regardless, it's a very atmospheric, oddly beautiful game. I suggest checking it out, especially because it's free.

If you don't want to mess with changing the system locale to Japanese and downloading a bunch of files, I suggest playing it online on https://ynoproject.net/.