is a beat 'em up shooter released as an arcade video game by Sega in 1990. It was ported to the Genesis/Mega Drive and Master System. The Mega Drive version was re-released on Wii's Virtual Console in 2007 and was also included on Sonic's Ultimate Genesis Collection for Xbox 360 and PlayStation 3. The game was also re-released on the Nintendo Switch Online + Expansion Pack in 2022. Plot A homicidal alien race is invading Earth, and the only thing that stands between them and world domination are a special forces team known as the "Alien Busters", composed of Karen (absent in the Master System version, named "Karla" in some versions), Garth (named "Gordon" in some versions) and Scooter (the robot, named "Slammer" in Master System and PAL versions). Gameplay Alien Storm is a side-scrolling beat 'em up. The game resembles Golden Axe, with a similar artistic style, three playable characters (a man, a woman, and a novelty character) and pick-up or power-up special attacks. The player (one player only on the Master System version, up to two players on the Mega Drive version, three on the arcade version) selects from the three different characters to embark upon a quest to save the Earth from an alien invasion. All of the Busters are playable from the beginning of the game. There are six missions to complete (eight in the Mega Drive version) with several stages, and each mission has the player blasting aliens, from the streets to the mother ship, where the mother of all aliens can be found. This task becomes increasingly difficult with each new mission, and the aliens are capable of hiding inside objects such as plants, post boxes, trash cans, drums, and other items. Each mission has an objective such as rescuing people or destroying a UFO. After defeating certain aliens, flying skulls will appear, which can be shot to collect life or energy. Energy is used specifically to power the energy-based attacks of the player's weapon (such as flames or electricity) and to use the much more powerful special weapons. In a similar format as other early Sega arcade games, each character has unlimited usage of various short-range attacks, i.e. punches, kicks. Along with these standard attacks, each character has their own individual weapon (Garth's weapon that shoots lightning is replaced with a flame weapon in the Master System version). Special attacks are also included,