Alien Storm

Alien Storm is an arcade game by Sega, later ported to the Sega Genesis and Sega Master System. The Genesis version was also released on Wii's Virtual Console in 2007.

Description
The aliens are invading Earth, and it's up to the "Alien Busters" to wipe them out and destroy their creator. The Busters consist of Karen, Garth and Scooter. Each one of them have their own unique weapons and special attacks. However these differences are all just cosmetic as they all play virtually identical to one another.

When you start the game, you can select any one of these characters to play as. There are 6 missions to complete (8 in the Genesis version) with several stages, and each mission has you blasting aliens all the way to the end, from the streets to the mother ship, where you'll meet the mother of all aliens. Unfortunately, blasting these aliens will not be an easy task, as they get tougher in every mission, and are capable of hiding inside objects such as plants, postboxes, trashcans, drums, and other items. Each mission has an objective such as rescuing people or destroying a UFO.

When you deal with a few aliens, flying heads will appear, which you can shoot to collect life or energy. Energy is used specifically to power your weapon's energy based attacks (such as flames or electricity) and to use the much more powerful special weapons.

Special weapons vary depending on the character you choose at the start of the game. For instance, Garth summons a U.S. Air Force starship that drops bombs across the street. Scooter will teleport out of his present location and leave a series of bombs that will blow up on the appearance of aliens, after which he will re-appear (In the Genesis version he just explodes, leaving his head, which his new body returns for). Karen calls down a nuclear missile, which incenerates every foe on the screen. However, using your character's special attack uses up a lot of energy, and if you don't have enough, you won't be able to use it.

At the end of some missions is an alien boss, which you must destroy in order to complete the mission. Also, at the end of every one, you have to enter buildings where you participate in a shooting gallery. The objective is to take out the aliens popping up from several locations with the building.

Storyline and gameplay
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), Garth (named "Gordon" in some versions) and Scooter (the robot, named "Slammer" in Master System version). In a similar format as other early Sega arcade games, each character has unlimited usage of various short-range attacks, i.e. punches, kicks. They also have the ability to use energy based attacks, such as a flamethrower or a special attack that destroys all the minor enemies on the screen at once, these use up the player's energy bar, however. The game has 6 stages (8 in the Sega Genesis version) that take the characters from the city streets to the alien mothership.

The majority of the game is played as a traditional side-scroller where the player must navigate their way to the right of the screen, killing enemies with short range attacks. After this the game play shifts from the side-scrolling game to either a shooting gallery perspective where you must take out the aliens that pop out of various locations or a running section that is similar to the side scrolling mode but plays like a horizontal shooter instead with projectile weapons.

There are few bosses in the game. The arcade original only features a single boss. However it has three distinct forms that it morphs between once one is defeated. The Mega Drive port has two of these forms as two separate bosses.

In the console and Japanese Arcade versions, Gordon has a red dress while Karen has yellow outfit. In the US arcade version, Gordon is dressed in Blue and Karen is Red.

In the Master System version, Karen is no longer present and Gordon's special Jet Attack is changed with Karen's special. (A ballistic missile) Also, Gordon's weapon which shoots lightnings is changed with a some sort of a flame weapon.