Yume Nikki is a game that has a ton of different versions as well as disparate kinds of content. In addition to this it's not a linear game, and as such playthroughs will be more-or-less unique. In this sort of a context it seems inevitable that certain elements of the game will impress themselves upon some players more than others. Different people will take away different things from the game depending on their experience and interpretation. This individual and subjective nature of the game is directly suggested in the player exploring Madotsuki's dream worlds. (i.e. her unconscious.)
But the most explicit mention of rorschach test's in the game is perhaps the character FACE. Far from resembling phallic imagery, FACE far more clearly resembles an inkblot test. The idea that FACE looks like phallic imagery is obviously a libidinal interpretation, which gives more weight to the desires of the Id. (Lol dongs.) This also suggests the interpretive and subjective nature of the game.
I don't even know how often people come to this chan, but I thought I'd leave this here.https://yumenikki.fandom.com/wiki/FACE