It’s quite a tradition for game companies to post something on April Fools every year. Three years ago, Karin made a very short game for the April 1st. I forgot I have this one until I accidentally found this in one of my folders.
Psychic Rain is about Amemiya Saya whose psychic power runs wild especially on a rainy day. One particular day when there is a surge of her power, she comes across to one of the two available guys in the game. Depends on how you look at it, one guy is the good end and the other is the bad end.