Pardon the double post. I just wanted to let everyone know that we've just put up a new version with quite a few improvements:
-Touch sensitive jumping and progressive sprint speed
-Various new art and animation
-Improved hit map detection (especially in World 4)
-Levels re-designed for a more progressive difficulty
We still have several known issues (the most apparent will be the fact that some platforms will occasionally disappear for no apparent reason), but it's definitely getting there. Please check it out and let us know what you think. Thanks guys!