Alien Attack

Description
Alien Attack is a first-person shooter featuring aliens. Technically it is a reskin of Mars Massacre by the same developer.
The goal is to defend a base against enemies bullets. The player's character is equipped with a laser cannon to shoot enemies. Friendly ships appearing in the sky from time to time should be avoided when shooting. It takes around fifteen shots from aliens to decrease the base energy to 0, ending the game.
The game has no win state, so the goal for the player's character is to survive as long as possible and get the highest possible score.