Messed-up Adventure Game IDK

Game controls:

Play

Also in a certain route, there's a "code" puzzle in Japanese that apparently noone can crack which I'm really sorry about. The answer is in Death Note anime episode 10 (Japanese soundtrack), so check that out. Also if you can read Japanese, hover your cursor over the top right corner of the paper. You'll find a hint button. Hold your left click to read the Japanese.