I like mechanics of this game and that every character has different movement. But I wish jump would be just a little higher (for the starting character), because I got offten stopped by a wall, that was just a pixel higher than my jump and it can be frustrating over time. Also checkpoints would be great. And smooth camera movement (for example use of Cinemachine component in Unity) would be nice addition, but this is not too essential for the game, but adds bonus points to game feel.
But I like the pixel art, monochromatic color palette and how every character has its own health. Good job.