Question...and suggestion.
Question: Why do stats just stop increasing at certain points? I know 99 is the cap, but there are times at which nothing happens on a particular stat.
Suggestion: Make an in-game tutorial and/or descriptor of stat distribution and results.
The achievements system is all messed up. I get all of the "fly for a certain number of seconds" medals after the first level. And no matter how many different combinations of flips I try, I can't seem to get the Combo flip achievments.