Per pixel collision detection - very cool. My game doesn't have this yet but it's a priority now. It looks simple enough to add too. At the moment I have a block around my character that I'm using to detect collisions. The problem with this is that he's wider than his feet, so he can hover over the edge of platforms, standing on nothing because the square around him isn't over the edge yet.
What per pixel collision detection does, is check every pixel in the image and see if it's colliding with the pixels on another image. It's on my to-do list. Now to do some real work :/
Thanks to Evan for linking me to this.
This is his true power. Or a glitch. Nice lack of background.