Large planets, populated by highly developed races, are able to protect themselves from alien invasion, and what to do with small peaceful planets. For them there is a special patrol, which regularly visits and checks the situation. You are on his team and today in Planet 51 Squirt Gun Patrol your mission is to protect the planet 51. A whole cloud of space aggressors flew here. Armada flying saucers dive on defenseless inhabitants, on the surface one-eyed monsters are planted and begin to rampage. Shoot the ships and monsters without touching innocent citizens, you easily distinguish them from the aliens.