Fun game, I think its only main issue is that deaths often bring you to "bad cycle" configuration of rooms with sliding blocks that cause you to just wait around. For example, in the 4 slidey spike blocks room with the red teleporters, when you die it resets you to a cycle where the blocks immediately move forward, forcing you to just wait. Same thing with the slidey upwards blocks room in the beginning of the game when you only have yellow jumps. Additionally, I feel like controls are maybe too tight with how you often can't even get on many circles in the beginning of the level without timing a jump, like when just having to fall off a ledge to get on something. Maybe consider adding acceleration, going from walk to full speed is tricky to work with.