Steer left or right; the squad runs and fires straight ahead on its own. On a phone swipe left or right anywhere on the screen, on a desktop use A/D or the arrow keys. Stand in front of what you want to shoot - a gate to grow its number, a tire stack to win its prize, the horde to stop it - and walk through the best gate.

Every bullet that hits a gate fills it, and each time it fills the number rises by one. A blue +3 you keep shooting becomes much bigger before you walk through it, and a red minus gate can be shot up into a plus. Each gate has a ceiling. x2 and x3 gates multiply your squad but do not grow, a red ÷2 gate halves it unless you shoot it enough to break it into +1, and a gold FIRE RATE gate makes the squad shoot faster instead of adding soldiers.

Stacks of tires with a health number and a gold prize on top. Shoot one down and you get the prize: extra soldiers, the next gun (Rifle, SMG, Minigun, Laser, Plasma), an airstrike that clears the road ahead, or a jeep or tank that joins your squad. Running into a stack you did not break costs you soldiers.

Walkers, runners, brutes (purple giants with their health above their heads - focus fire on them), armoured zombies with shields that halve your damage, bloaters that split in two, and leapers that jump over bullets. Bosses have a health bar at the top of the screen: a giant mutant at stages 9 and 15, a hive mother that spawns zombies at 21, a titan that matches your firepower at 27 and the biggest one at 30.

Kills and cleared stages pay coins. Power adds damage to every bullet, Rate makes the squad fire faster and Recruits adds a soldier to the start of every stage. Upgrades are permanent; guns, jeeps and tanks won from tire stacks last for the current stage.

No. Gatefire runs directly in the browser on phones and desktops - no download, no plugin, no account. It is free; the optional short videos give one squad revive per stage or a coin advance, and nothing is ever bought with real money. Your progress stays on your own device.