During the good old days of 8-bit home computers it was common practice for arcade games to make their way across to the home by way of lots of unofficial copies, many of them written by people at home for fun. For example, Pacman became Munchman, Puckman, Trashman, Gobbler, BigYellowEatingGuy and so on. All of these took the basic gameplay of the original, usually adding nothing except maybe changing the ghosts into something else in the process.
In 1986 Japanese arcade game company Taito did something similar when they released Arkanoid. The game was based heavily on Atari’s earlier Breakout, which came out some 10 years earlier. In Breakout you controlled a bat at the bottom of the screen which you used to bounce a ball around. At the top of the screen were some bricks which smashed when the ball hit them, scoring you points.
Arkanoid took this idea and evolved it, with the main addition being power-ups. Sometimes when you destroyed a brick, a capsule would fall down the screen. If you caught this with your bat (which in Arkanoid was actually meant to be a spaceship called a Vaus, but to all intents and purposes it was a bat) you were awarded a new ability, which ranged from making the bat bigger or smaller, making it sticky so the ball could be caught, splitting the ball into three or my personal favourite, giving you the ability to fire laser bolts to destroy the bricks.
Clearing all the blocks in Breakout rewarded you by refilling the screen with blocks so you could try again. Arkanoid did the same, but instead your new screen full of blocks would be arranged in a different pattern, some abstract, some resembling other objects such as one of the aliens from Space Invaders, another Taito game.
Other smaller additions were that some bricks needed to be hit more than once to destroy them, and some couldn’t be destroyed at all. There were also funny little shapes (presumably aliens) slowly moving around the screen which always got in the way of the ball just as it was heading straight for the last brick, or had just bounced off your bat.
Arkanoid went on to itself be ported to home computers with some rather good officially licensed versions, and indeed has been unofficially cloned many times itself. It has also spawned several sequel games, including most recently a version for the Nintendo DS.