This is one of the coolest puzzle games I've played in a long time. I love the way you made use of the space of the keyboard -- your level design is impeccable, not a wasted pixel. When I realized the trick to getting more space to move down (on level 3) I think, I felt like the cleverest guy.
You've made a wonderful little box of A-HA! moments here. I'd love to see what else you can come up with using these kinds of mechanics. Well done!