Avenger is a shareware shoot 'em up arcade style game from Finland for one or two players and which is a bit of a cross between Galaxian and Space Invaders. The game starts in the year 2254 with a cut-scene showing the space station Finlanda and her escort vessel in the Alpha Centauri system. A horde of mysterious ships appear from nowhere and, after a short battle, the escort vessel is destroyed. The player takes the role of a pilot returning to the space station after a holiday. They find the station is now a base to many strange ships which attack their vessel.The object of the game is to achieve a high score. Gameplay is very much in the Space Invaders style. In the single player mode the left / right cursor keys being used to move the player's ship from side to side while the Right Alt key fires the main weapon and the Right Ctrl key fires a secondary weapon. The enemy ships, however, attack in the style of the enemies in Galaxian, swooping around the screen as they attack.The game maintains a high score table and has two modes of play, normal and challenge. Two-player action is side by side with both players sharing the keyboard. The challenge mode is only available in the full registered version which has 55 levels.