Cosmic Guerilla is a ZX Spectrum video game developed and published by Crystal Computing in 1983. It is a non-scrolling vertical shoot 'em up similar to Space Invaders, converted from a 1979 Japanese arcade game by Universal. The game was developed in 100% machine code.

Cosmic Guerilla is a two-dimensional fixed shooter game. The player takes control of a laser cannon at the bottom of the screen whose movement is limited to left and right, and must fire at the aliens above. In contrast to Space Invaders the aliens are arranged in a single vertical line on each side of the screen, with their movement being towards the centre, one or more at a time, in an attempt to capture and remove the player's shields. The aliens cannot be hit by the player's shots until they begin to move, and the player may only fire one projectile at a time, preventing weapon spamming. Once a row of shields has been removed, one of the player's "lives", is exposed and able to be captured. Occasionally a very fast "mothership" will appear and traverse the screen just above the player dropping bombs.

There are six levels of difficulty along with four game modes allowing combinations of the regular game, bonus enemies, and faster aliens. There is also a two player mode where players take alternative turns.

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