A lovely and deeply-expansive Yume Nikki fangame that can probably boast having the largest explore-able world of any out there, due to its collaborative nature; "completion" of the game (regarding getting all effects and seeing an ending locked behind it) is made far less enjoyable than other fangames as a consequence of this, and I needed to look up the locations of two or three of them. Regardless, if you can find joy in the heavy variety of styles and locales, you may very well enjoy this one; it's considered one of the greats for a good reason, I'd say.
Certain links to different areas/events requiring certain effects is particularly frustrating due to the combination massive open world and sometimes-esoteric effect hiding spots though, so keep that in mind if it takes you a while to find certain keys you need to progress, like being able to tear down wooden barricades over doorways.