Great use of colour. It is clear to me that blue objects are hazards very early on in the game. The graphics and intro animation is charming. Sound design is very Gameboy-ish, but can sometimes be too harsh for me.
The jump feels too high and 'floaty' to me. It is also difficult to know where I'm landing or plan ahead since the screen is fixed to the player, though this is also due to the screen size restriction. Like many mentioned, having the game restart when dying is a bit punishing, but it's understandable with the time constrain.
Good work on it!