Yume 2kki (ゆめ2っき)

Yume 2kki (ゆめ2っき Yume Nikki, literally Dream Diary, but also a pun on the original game's title -- に, or "ni," means 2) is the original fangame that started it all. It is a large collaboration project from 2chan users and thus features a wide variety of worlds, effects, and ideas. Just like the original games, there is no overarching plot and the only goal is to explore and collect all of the effects.

A unique feature of 2kki is the inclusion of collectable wallpapers, unlocked by reaching certain areas or activating events. These can be found on Urotsuki's real world PC and serve as a large side-quest for the game. Collecting 138 of the 140 unlocks one of the game's four endings.