Protector takes the idea from Defender (1981): the player is controlling a ship over a horizontally scrolling landscape, able to fly to the left and right with different speed. Some residents of the planet are standing on the floor, with alien ships trying to kidnap them. The player has to prevent that by destroying all the enemy ships first. This can be done with the laser cannon or smart-bombs. If all enemies in a level are destroyed the level is finished. A radar helps to keep track of the enemies in the level.