Like others have said, this game doesn't really feel like a 90s-era, 16-bit platformer — it reminds me more of a Flash game, or maybe an Amiga one. It's good that you explain the controls within the game, but they aren't explained fully — you're not told that you can use arrow keys to move instead of WASD, or to use space to jump, for example. Retto's movement and jumping feel okay, but they feel pretty floaty in the air — and they also tend to slow down on walls, and I don't know if this is an intentional wall-jumping mechanic or not.