First of all, I love the concept of this. You had a great idea and it seems like you used your time pretty wisely to execute on the core of your concept. The art works well in its simplicity and cleanness, and I like the detail of applying an x to where you died previously, rather than making the player remember where all the hazards are. Being able to see the invisible hazards and platforms when you complete a level is a nice touch as well. Good job!