Really cool game! I really liked how the palette was used, as everything was nice and distinct. Everything is well-explained, given the restrictions in space & colour. I didn't have any problems with the platforming, and the difficulty progression was really good. I did run into some bugs though, unfortunately. The hitbox on the rat is a bit broken, where sometimes when you drop onto it, you don't kill it, but just land on it. Sometimes the rat then stops, but sometimes it moves and warps the pc to a random corner of the screen (once directly to the end of the level!), and I was able to reproduce the bug fairly easily. Also off-screen stuff is still loaded in, so you can activate the door to finish the chapter before the door becomes visible just by running off-screen at the end, and the left and right arrow keys work even though the player is never told this. This game is also fun to speedrun, I managed to get to the end of chapter 1 in 36.24s, but sub-30 should be possible!
(example of the glitch)