Beamrider‘s plot describes the formation of a beam matrix above the player’s home planet. With Beamships readying to attack, the player has to infiltrate the matrix and defend their planet.
Beamrider is an arcade shoot 'em up that is played out on a tilted grid, with the player's ship at the bottom of the screen, and the enemy beamships flying down to attack (in forced perspective) from above. The player's gun has a fairly short range (about half-way up the screen), but the three torpedoes available for each sector can go all the way up to the top.
In total, there are 99 sectors to battle through, with the latter sectors being much harder to clear than the earlier ones. Before they can progress to the next sector, the player has to destroy the sector's sentinel ship.