In the game, the player has 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 (rescuing hostages also restores Harry to full health), and upgrade to different kinds of ammo by using ammo dispensers. The player needs to collect coins dropped by killed enemies to buy this ammo. They can also pick up other power-ups with various effects, including a wrapped gift (additional ammo for Harry's current weapon), a money bag (30 additional credits; coins dropped by enemies are worth 5 credits each), and a 1-up icon (an extra life, plus full health). The game progress can be saved through the use of computer terminals scattered across the levels. To advance to the next level, Harry needs to rescue all the hostages, then use the elevator.