Initially the only Game Mode available in
Cel Damage is Smack Attack. It consists of selecting a character and then frantically driving through the area you've selected, picking up weapons and power-ups, and trying to destroy all of the other characters as often as you possibly can.
To unlock the next Game Mode, Gate Relay, you have to be the first one to smack the other characters a total of 500 times. In Gate Relay, you are required to pass through gates a set number of times. In the final game mode, Flag Rally, you must collect four flags and deliver them to the winner's circle before your competitors.
The various characters in Cel Damage all have different attributes, as each is rated in Top Speed, Acceleration, Turning, Deceleration, Traction, and Weight. You can tell the difference between each of them, but ultimately, speed and turning seem to be the deciding factors, as you must quickly maneuver to the best weapons, then take out your opponents quickly in order to win.
You can only pick up a single weapon at a time, which means there's little to do but roam around and take out other characters. There's not much depth to any of the Game Modes, and although the areas are interesting, once you've seen them all, there's little else to do.