X-Moto is a 2D opensource motocross platformer where physics is at the heart of the game. In other words - to achieve your goals, you must
... you'd better watch the video of the game :) That's the best way to understand what kind of game this is.
Another important thing is - the level editor. You can make your own. Trade with friends or download from the Internet.
Although the graphics are simple and completely 2D, the game uses a 3D accelerator for faster rendering. This is why your video card must support OpenGL (unless you have really old PC it will).
During the game, you have to collect strawberries. They are needed to pass the level, which is done by touching a flower. What can get in your way is the challenging terrain and various messy thorns that shouldn't be touched. Some levels have terrain elements that move. They are usually placed with a purpose. ;) Ah, yes ... and be careful not to fall on your head, because it's not good. :)
In the game there is also the so called "ghost". It can show a recorded replay of the level during your next play.
There's more to say, but you'd better see for yourself. The game is a little weird, but very addictive.