Abysmal
Absolutely atrocious.
To start, playing with the keyboard is impossible. And I can almost say that literally. Simply put, the bike does not turn nearly as sharply as it should when using the keyboard. No matter how perfectly you do everything, you _will_ hit the outside wall of the turn. Also, your bike doesn't go anywhere near as fast as your opponents - I was hard pressed to even get into 5th place! And you start at 6th!
Playing with the mouse is a little better, but still not great. The turning is improved, but it still isn't sharp enough for some of the tighter turns. You do go faster with the mouse, but not fast enough to get into 1st, from what I can tell. All in all, the controls need major tweaking.
The graphics are also terrible. I mean, the 3D effects were nice, but those horrible 2D backdrops absolutely killed it for me. The game would have honestly looked a lot better without them.
Lastly, the depth was seriously lacking. You can either do a race or do a race with a different control scheme. Either way, the game tells you your time and place at the end, and then you're done. No unlocking, no story, no further levels, just one race and you're done.
Needs some serious rethinking.