Gameplay seems easy at first sight but is impossible to master as soon as you try to fly your rocket car.
Play with friends and you'll never stop saying "one more game".
Play in competitive and get angry at yourself when you miss the ball, angry at your opponents when they fly their car better than you do but also get a chance to experience that feeling of great joy when you hit an overtime game-winning goal.
Play in 1v1, 2v2, 3v3, 4v4 or... if you're tired of the same old rocket soccer... play on the labs map and their weird terrain. Why not play rocket basketball or even rocket hockey while you're at it?
After a month of play, I can tell you I'd buy this game for more than twice its original retail price without hesitation ;)