In this arcade title, the player controls SWAT, a shooting hoverboarder. The game appears to be set underwater, and each stage is almost a fixed background - though there is a tiny bit of up-and-down scrolling.
Aliens resembling sea creatures try to build a tunnel from the bottom of the stage to the top, which is your home-base.
If you touch an alien you die, and if an alien builds a tunnel right up to your home-base it gains control of it and shoots jets of fire down at you.
Besides shooting a rapid-fire laser gun, you can fire torpedoes which attach to tunnel sections and explode on a timer, allowing you to get out of range. You die if caught in the blast. Besides being able to destroy tunnel sections with your missile weapons, you can also shove them to the side.