Flipping back and forth between Gravity Rush, Motorstorm, Wipeout and Jet Set Radio. Admittedly none of them are really bad except for JSR which is trash of the highest order and I'm not really versed in the racing genre enough to properly criticize or find flaws in motorstorm and wipeout.
Gravity Rush I like but I have serious control issues with that game that stop me from getting the most out of it. I still haven't adapted to any of the motion crap or even the basic gravity shifting, not to the point where I can pull of gold medals in challenge races.
Ouch.
Gravity shifting should the the thing that you focus on first. Motion grinding is fun if you can adapt, but gravity kicks are faster, and mastering gravity shifting is the first step toward learning how to aim your kicks.
EDIT: Oh, you're skipping the challenges. Nvm then.