Here are the rules of the game, taken from the main game page:
OBJECTIVE
survive the zombie apocalypse with your kitted out muscle car!
Accelerate to gain heat, and use it to burn the zombies when you drift.
Their numbers grow, as does your cars speed.
DRIFT. INCINERATE. SURVIVE.
CONTROLS
[W][A][S][D] (tap) - change directions, initiate DRIFT
[W][A][S][D] (hold) - slow down, release to speed up again
[SPACE] - when heat gauge full, create a defensive ring of fire
Get hit once, no biggie, you heal in 3 seconds.
Get hit twice, yes biggie, GAME OVER!