The first level is pretty hard to be a first level, I think is even harder than the next ones hahahahaha, your first level works, to complete it you have to learn the mechanics, but a simple first level will be much better to teach the player the mechanics (in my opinion).
Speaking about levels, they have a really good design , but are very linear, adding some sort of liberty can make it more fun.
You should add a button to repeat the level instantly, because some times you can't complete the level and you have to kill yourself, to repeat it hahaha.
Closing the game by pressing escape is a very bad idea.
But other than that is really cool.
The game is solid, the controls are good , the visuals are awesome, and the music is good.