Very good entry, full of charm.
Love how bold you were just adding a mandatory binary puzzle to a jam game. If you know how it works it's trivial, if you don't, then good luck solving it. I appreciate the respect you have for your player's intelligence.
The case may be a bit easy to crack, only one suspects has a motive, an opportunity and no alibi, but it's still very pleasant to see it come together as you gather evidences. Gameboy investigation games is such a rich vein left untouched. I especially adore your final Danganronpa-like explanation of the murder. Very flavorfull.
The lack of sound is a pain, it would have been the final touch to an all around very solid game.