Playing the roll of Harry in Alien Carnage, you have to shoot zombies and aliens with his flamethrower and other weapons, rescuing hostages along the way. Instead of jumping, Harry uses a jetpack to reach higher platforms. His jetpack shares ammo with his flamethrower, which means it is best for the player to use both sparingly. Harry can eat and drink junk food to gain health, and upgrade to different kinds of ammo by using ammo dispensers. Harry needs to collect coins dropped by killed enemies to buy this ammo. He can also pick up other power-ups with various effects. He can use computer terminals scattered across the levels to save his progress.