It's just you and your disintegrator cannon against the might of the Argons. You must protect the prison from the Argons as they strike to liberate their kings, imprisoned by you for their crimes against the Empire. The Argons attempt to dismantle the prison brick by brick until they have freed their rulers. If they succeed you are duty bound to commit suicide. There is no respite, for each wave of Argons you destroy, another more determined one will take their place.
The game features good, colourful graphics, smooth action and good sound effects. You start with three cannons and there are nine levels to negotiate, with an extra cannon awarded at level five.
Choice of CAPS LOCK and CTRL keys is tiring on the wrists, but the game is readily playable nevertheless. I'm surprised at the number of arcade-type games released these days without a joystick option; it would certainly be a worthwhile addition here. Sound on/off and a pause facility are a couple of useful features.
The game is addictive and fun to play - you feel you can always do better next time.