Nice art style.
I was a bit confused, the first time I got a special key, then went to the settings, because the textbox said something like that, then realized I had to start the level again from the beginning. But once I figured out how to use them the special key where a glorious addition to the gameplay.
When walking between different tiles (the black boxes and the brown bricks) I got stuck sometimes, when I did not jump. Would be nice if I could just walk across them. Also the walking distances where a bit long sometimes, especially when I hat to restart a level a few times.
But those are minor points. All in all, this is a really enjoyable game with very well designed levels. Congrats on this great entry!