Sub Terrania

The game takes place in a side-scrolling underground environment. The controls are based on the classic computer game Thrust, with the player rotating the ship with the directional pad and thrusting forward by pressing the B button. At all times, gravity is pulling down on the player's ship, which works to the player's advantage to conserve fuel.

To beat each of the game's 10 levels, the player must complete various mission objectives, which are outlined before the level begins (with the exception of the last three levels). The bulk of the missions involve rescuing prisoners, collecting sub modules (to allow your attack ship to go underwater), and defeating alien bosses. To make things more challenging, your ship has a limited fuel tank, which must be constantly recharged by collecting fuel canisters, which are scattered throughout the levels.

There are various other elements that make it easier for the player to be able to finish without running out of fuel-- mining rails are suspended throughout many levels which you can ride on with your ship, which turns off fuel consumption while allowing you to freely slide along them while shooting. There are missile canisters and shield upgrades, along with a "Mega" attack which is released at the beginning of each volley of fire and slowly recharged.