 This level closely parallels "Space Invaders", with the aliens methodically sweeping from side to side, firing at the player, dropping slightly on each pass, and increasing in speed as their numbers dwindle.Unlike "Space Invaders", the player has no protective barriers and must also dodge fiery meteors.Subsequent levels throw different challenges at the player, such as carefully navigating down narrow, winding tunnels, dodging and attacking oncoming aliens and passing through pulsing energy barriers.