From the depth of space come the hostile Reegs. Fly X15 over the desolate landscape to protect the Cannisters from the attacking forces. Landers follow the shape of the landcape in search of Cannisters. If a Lander grabs a cannister and succeeds in carrying it to the top of the screen, it turns into a mutant.

Shoot the alien shop and catch the cannister as it falls. If it falls a long way, it will disintegrate on impact.

Cruisers unleash a convoy of buzzers when they are hit.

Activating a smart bomb will cause everything on the screen to disintegrate. On higher waves, each mine layer will launch three killers unless destroyed beforehand.

If all the cannisters are destroyed then the land disintegrates and you have to contend with a swarm of mutants.

Lander .................................. 10
Mine Layer .............................. 20
Crawler ................................. 30
Mutant .................................. 40
Killer .................................. 40
Cruiser ................................. 40
Buzzer .................................. 50
Destroying Cannister ..................... 0
Cannister landing safely ................ 60
Cannister caught while falling .......... 80
Cannister returned to earth ............. 80

A bonus is awarded for each remaining cannister at the end of every wave. An extra life and an additional Smart Bomb is awarded every 1,000 points.

A - Up, Z - Down, RETURN - Fire, SHIFT - Thrust
SPACE - Reverse, CAPS - Smart Bomb