It's a cool game, but checkpoints are really important. I died to the first enemy and was brought back to the very beginning. I also think some simple sound feedback when pressing the buttons would be really good.
Actually, there is a sound when pressing the buttons! Just listen more closely, it´s pretty loud. Yes, i know about the checkpoints, that´s a major flaw in my game, but that´s why i participated: To learn something new, and improve my games! :)