great game overall, very addicting and fun. Also VERY intense at around 900+. I have yet to reach 1000 on harder. D=
The sound effects do a great job of pulling you into the experience, as well as everything else.
The high score functionality keeps me going back to try to beat myself over and over. =P
However, one of the weirder problems I've encountered is that from time to time, stuff just quits rendering for a few moments. I might be traveling through some tunnel and then BAM, blackness.
Also, the randomness of the obstacles can really screw you over sometimes. You might be ejected from a twisty-pipe right into one of those massive squares, and one would be hard-pressed to avoid something in that time frame.
Other than those, it's a damn solid game, and I imagine I'll keep coming back to it again and again.