Warlords

Warlords is an arcade game released in 1980. It was ported to the Atari 2600.

Gameplay
It's like a four-player battle version of the classic game Breakout. You play as one of the four defenders of a castle that's being bombarded by a bouncing fireball that inflicts damage on the castle walls it hits. You use your shield to deflect the fireball before it hits the walls deep enough to open a destructive path to your warlord, while also using the fireball to inflict damage on your opponent's castle walls in order to destroy their warlords. In the arcade original, destroyed warlords will launch an additional fireball into the playfield for increased challenge of survival.