There are 8 tracks, in both Left-Facing and Right-Facing versions. (Your vehicle faces either Left or Right at the beginning of the race)

There's a sequence of 2 tracks, then 3 tracks, then 4 tracks, then 5 tracks, etc, until all 8 tracks are unlocked. Each sequence will alternate between Left-Facing and Right-Facing tracks.

The last track (Hurricane Gulch) becomes available at Race 34, and the opposite-facing version at Race 42.

There are 99 races total. After beating Race 99, you are kicked out to the High-Score screen.

Qualifying Races: Facing Left, Race 1-2: Fandango, Sidewinder Facing Right, Race 3-5: Fandango, Sidewinder, Wipe Out Facing Left, Race 6-9: Fandango, Sidewinder, Wipe Out, Big Dukes Facing Right, Race 10-14: Fandango, Sidewinder, Wipe Out, Big Dukes, Blaster Final Tournament of Champions: Facing Left, Race 15-20: Fandango, Sidewinder, Wipe Out, Big Dukes, Blaster, Cliffhanger Facing Right, Race 21-26: Fandango, Sidewinder, Wipe Out, Big Dukes, Blaster, Cliffhanger, Huevos Grande Facing Left, Race 27-34: Fandango, Sidewinder, Wipe Out, Big Dukes, Blaster, Cliffhanger, Huevos Grande, Hurricane Gulch Facing Right, Race 35-42: Fandango, Sidewinder, Wipe Out, Big Dukes, Blaster, Cliffhanger, Huevos Grande, Hurricane Gulch Races 43-99 repeat the tracks of races 27-42.

There are "Easy" tracks, and "Hard" tracks. The computer opponent basically plays unfair on "Hard" tracks, and exceeds your maximum speed without consuming any nitros. A good player can still win on the "Hard" tracks.

"Easy" Tracks: Fandango, Wipe Out, Cliffhanger, Huevos Grande "Hard" Tracks: Sidewinder, Big Dukes, Blaster, Hurricane Gulch

There is also a hidden "Difficulty" variable. The value starts at 32. On every race except for 1, 3, 5, 7, and 9, the difficulty value increases by 2. By the end of the game, the difficulty value is at 220. So races 43-99 do get steadily harder over time.

(If you want to test the difficulty value, it's memory address 7E2. Try beating Fandango at 255 Difficulty!)

Trivia: If there was no 99 race limit, game difficulty would reach 256, and wrap back to 0 at race 117.