Dustforce is the midweek madness this week and IMO a bargain at £3.49. It's just been updated with a level editor and sharing website as well so there should be endless gameplay.
Edit: Here's an example of a level creating with the editor:
Edited by Roarster at 08:56:52 02-05-2012
Edit: Here's an example of a level creating with the editor:
Edited by Roarster at 08:56:52 02-05-2012
