A bit of racing, a bit of trick motorbike obstacles, a bit of physics and you get a challenging but fun game.
Gameplay: 4/5
+ The controls are very tight and precise, and given that most of the tracks rely on a delicate balance of physics this is essential. Although it may be hard to get the hang of at first, once you've sunk some hours into it you begin to grow very accustomed to the maneuvers. Many people complain that this game (and its achievements) are way too hard, but on the contrary: the difficulty level in this game is very fine-tuned. You will have no trouble getting through the Easy levels; the Medium stages will make you rethink how to get to the next checkpoint; and Hard stages are some of the most grueling, difficult challenges you'll have to put up with. But isn't that what a Hard level should be? I have to say that it takes a lot of patience, observation, and practice to complete the Hard levels and you should not expect to beat them quickly. But it is definitely possible. In my opinion, this game can be extremely frustrating at first but once you've mastered the controls it is insanely fun and challenging.
Story/Presentation: (N/A)
+ No real back story. You're just some guy on a motor bike going through insane obstacle courses.
Graphics: 4/5
+ Although essentially a 2D game (you can only move left and right, and go up and down off of ramps) the models and levels are impressively 3D. The graphics can be trimmed down a lot if you are running a weak computer, but if your computer can handle it then turn up all the effects and marvel at the animation, lighting, and effects.
Value: 4/5
+ A system of leaderboards let you compete against the top scores around the world. Granted, these top scores are pretty much set in stone by some of the best players by now, you can still compete with yourself and players near your score. It's also challenging to try and get through all the level with zero faults. The achievements truly live up to their name, too, and it will surely take you some time to get them. Essentially, this game offers a lot of value whether it's just trying to beat a hard level or trying to cut down your time/faults in a level you already played. For a low-priced indie game I've put more hours into this than some expensive triple-A game.