|Mode||Single player only|
In Space Invaders, an overhead formation of invaders would appear over the player’s laser base, moving from side to side, coming closer with each time they reached a screen edge while dropping bombs all the while. The player had to destroy as many invaders as possible by shooting them with their laser base. A high scoring U. F. O. would also appear several times during a level.
Invasion is a clone of Space Invaders with only a few minor changes.
During a game, a group of invaders appears over the player’s laser base and starts moving to the side; once they reach the edge of a screen the formation will drop down a notch closer to the player’s laser base. The invaders also start shooting, which being hit by an invader’s fire will cost the player a laser base and the game will end when there are no more bases left in reserve. If any invader reaches the very bottom of the screen, this will also end the game.
A bonus U. F. O. will also appear during a wave that is worth a lot of points if hit.
It is the player’s duty to shoot down as many invaders as possible; once a screen of invaders is wiped out, a new level will start. The player also has four bunkers they can use for protection against invader fire, although being hit by either an invaders’ or the player’s laser base’s artillery will wear down a bunker. All bunkers get refreshed at the beginning of a new level, however.
- Row 1-2 invader–10 points each
- Row 3-4 invader–20 points
- Row 5 invader–30 points
- U. F. O.–random amount
- Start game–x or z key
- Move laser base–left/right arrow keys
- Fire–x or z key
- Pause–Enter or p key
- There is a nod to the original Space Invaders in the game, as an outline of the moon can be seen at the bottom part of the screen, as this was originally an overlay that was situated inside the game’s monitor.
- Several changes from the original Space Invaders includes the bonus saucer coming out when there are as few as only one or two invaders left, unlike nine on the original. It is also smaller, is worth more points than on the original (400 max vs. 300 on Space Invaders) and doesn't come out as often during a level. The invaders don’t get closer and closer to the player’s laser base with each new wave, unlike with most Invader games in general. Reserve laser bases appear where the player’s previous laser base was hit, not at bottom left of the screen unlike with the original Space Invaders, plus bases also fire in more rapid succession than with the original.