In the arcade game Tempest, players controlled a blaster that could move around the outermost lanes of a bunch of geometrically-shaped levels and fire at ships that emerged from the middle or innermost areas of those levels.
Bedlam, however, was a "Tempest in reverse", where players' ships (resembling the Millennium Falcon from several of the Star Wars movies) sat in the middle of sectors while ships emerge from points of those sectors and came inwards towards the player. Players turn their ships left and right and can spin them around quicker with the Fast Rotate button. Also, Zap, like the Superzapper on Tempest, will destroy everything onscreen and can only be used once per sector.
There are several different types and mannerisms of enemies as well as sectors. Getting rammed by an enemy will cause the player to lose a ship in reserve and the game will end once the player has no more remaining ships.