You really need to work on the Framerate issue, use the tips from sPIKe.

It cant be that something with those bad graphics runs like GTA IV on 1920x1080 at full details on a Voodoo Graphics card.

EDIT 1: Also, what scale have you built this game in?! I started thegame with the highroad.wdl in an effort to get to the console and adjust a few setting to get a bit better performance, but even at camera.clip_far = 10000 i can barely see further than the player character. You did something wrong here, really wrong.

EDIT 2: I'm not saying this to make you feel bad. But perhaps you should really start with something smaller. Or if you really insist in doing this project: I recommend starting again from scratch, this time, with performance in mind.