Area 51: Site 4

Area 51: Site 4 is a light-gun shooter and picks up where Area 51 left off. It has two game modes: field exercise and adventure. Training levels are short missions where the player must finish "training challenges" and a "real mission" in any order. Against a video backdrop with improved graphics, you shoot various enemies that appear on screen such as zombies, giant maggots attacking infirmary patients, aliens trying to roll over a bus, plus alien ships, missiles and turrets. A giant red alien with multiple limbs is the final mission boss that must be defeated along with other aliens and zombies.

Player lives in game are lost if an enemy hits you, if you hit a fellow S.T.A.A.R. team member, letting the bus tip over or failing to meet a quota of aliens or equipment. By targeting certain objects, players can get extra points or weapons. There are secret rooms where you can get more points by shooting targets without being fired upon.