I hate to burst anyone's bubble that uses this trick, but if you go into a quest battle, and lose, you won't lose any energy. Kind of a dirty trick if you want to level up but ran out of energy.
If you need a quick way to level Assassin, go to Quick Match, set the map to Facility, max enemies on the enemy team, only you on your team, CtF. Hit 30 no problem with this method, haven't tried it for other classes.
Money-making in the game is FAR too slow. It's a small game, sure, two courses, but it takes a long time to save up the money to get all the highest level items even if you're getting first place and hitting coins. Other than that, if there were a few more courses and more of a difficulty curve where the opponents scale with every course, I'd be more impressed. 3/5
I noticed that too, Coy, and the pistol is decently powerful, so rapid-firing it is handy. Only problem with that is it lags the game so bad, you have to wait a while before you can move the elevators.