You need all 12 keys to unlock the Prototype. Collect all four Mountain Dew cans and you'll unlock the Mountain Dew Racer.
Submitted by Duros Bith
Cheat Menu
To access the cheat menu, go to the setup screen and hold L + R + Z. While still holding them press all four of the C buttons. If done correctly under audio should appear cheats.
To access the codes in the cheat menu simply put the cursor on the code you want to access then enter one of the codes below:
Massive Mass
Hold L and R and press C-Up, C-Down, C-Left, C-Right
Killer Rats
Hold L and R and press Z, Z, Z, Z
New York Cabs
Press R, L, Z, C-Up, C-Down, C-Up
Resurrect In Place
Hold Z and C-Left and press C-Right, then hold Z and C-Right and press C-Left.
Frame Scale
Hold Z and C-Down and press C-Up, then hold Z and C-Up and press C-Down.
Tire Scaling
Hold Z and C-Left and press C-Right, then hold Z and C-Right and press C-Left.
Auto-Abort
Quickly press C-Up four times.
Game Timer
Hold Z + C-Down, press C-Up, then hold Z + C-Up and press C-Down.
Submitted by Joe Donato, Brendan Lim, and Sooky Smooth
Invisible Car
At the car selection screen press Up, Down, Z, Left, Right, Z, Right, Left, Z + Down, Up, Z. You should see a video of the car driving with only 4 tires showing.
Submitted by Bryan Norton (MrHat9080@aol.com)
Los Angeles Underworld
This is a game glitch. When traveling north at a high rate of speed through the water way shortcut on the Los Angeles level, you can use the slanted dirt wall on the right of the exit ramp to jump over the top of the road barricade. If completed successfully, you will fall through the road into a dirt underworld where you can drive seemingly forever as L.A. goes by overhead.
Submitted by Doug Cullum (douglas@cullum.com)
Midway Track and Rocket Car
To get the Rocket Car, place first overall in the Circuit Mode. In addition to the car, you will also find a secret track, letting you drive through Midway's gaming studios.
Submitted by Duros Bith
Mountain Dew Prizes
You've probably noticed a Mountain Dew floating around somewhere. There are four in each level. If you collect all four, you get a Mountain Dew hotrod. I'll tell you how to get them on Las Vegas.
When you enter the strip(road with palm trees in the middle)listen for kids yelling, and when you do, look for an opening to the right. When you go through, turn right and go slowly up a ramp on the building. When you are on the roof turn around and go the wrong way and you should see a Mountain Dew, so get it!
Go to the Stratosphere Tower (you will hear people yelling) and turn right. About 2 seconts later you should see a coppery fence to the left and there will be an opening, so go through it (Mountain dews 2, 3 and 4 are here). Go through another opening and a Mountain Dew is behind a tree (3 and 4).
Follow step two until you go through the two openings. You should pick the taxi because you have to RUSH! If you go fast enough you'll jump high and get Mountain Dew 3. If you land on the building without blowing up, go to the edge and go left. Fall off slowly and you should get Mountain Dew number 4.
That's all the Mountain Dews, but try selecting your car on the Vegas track and you will find a new car.
Submitted by Travis Yarris (elizy@inreach.com)