If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Space - brake.
Z - nitro.
Your mission!? To get out of this dammed hell hole of a town as soon as possible! A deadly virus has circulated around the world and now it has hit your home town, your only chance is to grab your truck and destroy all that gets in your way. Drive the tractor, kill zombies, buy useful upgrades and get out of town as fast as possible. Good luck man, you will need it!