Namco‘s groundbreaking Xevious gave you a ship (the Solvalou) that could fire both a laser at flying targets and drop bombs on ground targets. Two fire buttons… Innovative in arcades in 1982.
Xevious also had an atmosphere all of its own. The warbling electronic sound effects are very distinctive. As a shooter it is quite tough too.
Namco‘s Xevious is probably more influential than a lot of people give it credit for. Graphically it is crisp and colourful, and gameplay wise it is precise and difficult. Xevious‘s boss encounter at the end of the game is still a sight to behold. Again: an innovation back in 1982, although when you beat it, the game just restarts from the first level. Considering how early the game was in terms of its place with arcade history, Xevious can be forgiven for its shortcomings.
Xevious definitely set a few trends back in 1982 though. Scrolling landscapes were the new ‘in thing’ after this game introduced them to the scene.
More: Xevious on Wikipedia