Centipede is a vertical shooter developed by Atari Inc. that was originally released in 1980 as an arcade game. In the game you control a strange craft that has been described as resembling a snake head or human head, shooting bugs that come down from the top of the playing field. A centipede will snake back and forth down the screen until the player successfully destroys it, thus completing the round.
(Segment: 10 points, Head: 100 points)
The centipede is a multi-segmented insect that descends on the player from above. It moves from side to side through the mushroom patch, moving down a level only when it reaches the side of the screen or hits a mushroom. When a segment of the centipede is hit, it turns into a mushroom. If the player shoots one of the middle segments instead of one of the end segments, then the centipede will break into two independently-moving centipedes which must both be destroyed.
The flea will appear when the number of mushrooms on the playing field starts to get low. As the flea drops from the top of the screen, it creates mushrooms in its path. The flea takes two shots to be destroyed. When it is hit for the first time, its rate of descent increases greatly.
The spider moves from left to right on the playing field near where the player's gun is. It destroys any mushrooms that it comes into contact with, but will also destroy the player if contact is made. The spider can be killed with one shot, and the amount of points it is worth changes depending on what its distance from the player is.
The scorpion appears and slides from one side of the screen to the other. Any mushroom that the scorpion comes into contact with becomes a "poison" mushroom. If the centipede touches one of these poison mushrooms it becomes sick and will plummet down the playing field towards the player.
The Mushroom: Nature's Cover System
One of the fundamental objects in the game is the mushroom. It blocks your blaster from moving, it can be shot up for a single point, it can be left partly damaged so that when you die it regenerates and gives you five points, it can be poisoned by a scorpion (and then regenerated as if it were damaged for 5 points when you die), it can be used to make centipedes behave more predictably, it is created by fleas and eaten up by spiders.
The ecology of Centipede is fundamentally dictated by the placement of these little creatures. Take care not to kill off too many or you'll be plagued by fleas, yet keep most of your area clear or you may be blocked from movement at a crucial point in a round. Mastery of the mushroom means mastery of yourself, grasshopper.