Majestic Twelve: The Space Invaders Part IV/Gameplay

Controls

 * Joystick: Use the 2-way joystick to direct the blue CG30 (or the red one if you're player 2) across the bottom of the screen; they can't wrap around.
 * Firing Button: Use this button to make the blue CG30 (or that red one if you're player 2) fire shots up at the invaders; some shall take multiple hits.
 * Special Weapon Button: Use this button to make the blue CG30 (or the red one if you're player 2) use a special weapon after gaining its powerup.
 * 1 or 2 Player Buttons: Push these buttons to begin the game as player 1 or player 2.

CG30
These two cannons are the protagonists for this game, and you must use them to destroy the invaders' formations; direct them left and right, to choose a position to fire from, then time your shots so that they arrive at the location of an invader that you are trying to hit. There are no longer any shields to protect them from enemy fire - but, when either of them collects an "A" powerup, four of them will fly into view from the left and right sides of the screen. Each hit on them from the underside will push them further into the air and any invader that touches them shall die immediately; however, they will automatically explode at the end of the current round. Getting hit by any invader's bullet will result in the loss of one "shield" (they start out with between none and three, and can earn up to eight, by collecting "S" powerups) - and, if they get hit by a bullet while they do not have any shields at all, they will explode (costing them a life). To the left is how they appear in the ground-based worlds, while below is how they appear in the air-based ones:

Regular Invaders
The main types of alien invaders still behave the same (again); they remain in formation, as they advance towards the bottom of the screen. The entire formation will either circle around as they move downwards, move to the right or left until the far column reaches the side of the screen then drop down and move back towards the other side of the screen, or move downwards - and the lowest invader of every column shall fire bullets down to the ground (and you will receive 10 extra points for every one you block, or for the bullets that cannot be blocked, attempt to). If any one invader manages to reach the bottom of the screen, both CG30 will die immediately (regardless of how many shields they have remaining), as opposed to immediate game-overs.

UFOs
As in the four previous titles, UFOs appear randomly, over the formation; they will appear on one side of the screen, and cross over to the opposite side. During this time you can attempt to shoot them for bonus points - and the point value that is awarded once again appears to be random, but now ranges up from 50 to 6400. They'll also leave powerups behind that fall down to the bottom of the screen and bestow their effects on both CG30 when collected.