Simple, yet effective!
You've been playing too much Portal, haven't you? :P
The concept and the art are both so simple, yet so ingenious and fun! The level design was good, there weren't any loopholes, they were somewhat challenging yet not too frustrating. Mysterious narration is great. High score boards are good... let's see... putting a bit more character into the mysterious narrator, or the main character, or something would be nice. More puzzle elements would make for more challenging levels in the future, if you decide to do more. I kind of half-expected to be able to avoid the pitfall at the end somehow, like flip around to avoid it... but you know.
You deserve a cake. And a 8/10.