Super Space Invaders '91, also known as Majestic Twelve: The Space Invaders Part IV, is an Arcade game released in 1990 by Taito for it's F2 Arcade board. This version features the classic Invaders game-play intact, but adds a slew of new alien invaders and power-ups to the mix, together with the vastly improved graphics that introduce colorful new backdrops.
The original game's flying saucer still makes an appearance, but instead of merely awarding bonus points when shot - as in the original game - it now drops a power-up pod for the player to retrieve. Power-ups include shield, faster shots, a laser (activated with the second button) and a giant butterfly, which freezes the invaders for a limited time.
One of the game's most memorable features is the "Cattle Mutilation" bonus screen, in which the player must protect a herd of cattle from a number of fast-moving saucers, intent on stealing the animals. If a cow is snatched, the player must shoot the relevant saucer to free it, being careful not to actually shoot the cow itself. The '91 incarnation also introduces bosses to the series for the first time; giant, screen-filling aliens that require several shots to kill.
Another major difference to the previous games in the series is that if an invader reaches the bottom of the screen, the player will simply lose a ship (in the original, the game would end once an alien had landed). Also, the player's ship now comes equipped with a shield that can withstand several hits. The shield's strength is depleted every time it takes a direct hit from one of the invaders, and too many hits will result in the shield disappearing altogether. A direct hit on an un-shielded ship will result in the loss of a player life.
Story[]
Years after the Invaders unsuccessful invasion of Earth, the Invaders have invaded Neptune and Neptune's planetary shape has turned itself into a Black Hole. The whole Invader fleet have begun their invasion into the Solar System until they reached Earth using Saucers that came from Neptune and spread across the Galaxy, creating huge bases for their Invasion Force. A list of Images of the UFO sightings was located in Earth and the common UFO, a Walker UFO and finally a Ball UFO were shown, Earth's forces hasten and developed a Laser Cannon that can transform as a Tank and a Space Fighter, they called it CG30, a prototype laser cannon that can kill the Invaders in ground, sky or space combat. They called this Operation as MJ-12. the fate of Earth and the Solar System depends on the CG30.
MJ-12 Gameplay[]

Zone Selection in MJ-12 (Take note each zone you selected affects the ending and boss fights you encounter.)
Similar to Darius II, the player must select proper zones in order to get the good ending, one must select from the map and choose the stage depends on your liking, if cleared, you can pick the other stage. the one with the " ? " one is the Final Zone, you cannot select this zone manually and is automatic.
Just like the gameplay, alongside with the formations from Return of the Invaders, it comes with a twist of a Boss fight. The bosses will appear on some respected fights, after fighting two bosses or three, the True Final Boss appears.
CG30[]
You pilot the Prototype Laser Tank/Space Fighter CG30, it is well armed, capable of rapid firing shots and shields to protect it from harm, shooting UFOs down powers your Tank/Fighter with different weapons and also powers up your shot and enhances your shield, enduring numerous hits.

CG30 in Space Fighter mode

CG30 (Blue) Player one

2 player version (in red colors)

CG30 in Space Fighter mode (2 Player Colors)