Alien Shooter: The Experiment (2005)

Alien Shooter: The Experiment is the second add-on to Alien Shooter. This new expansion pack adds five new missions to the game but unlike the previous expansion also introduces new playing fields such as houses, playgrounds. This expansion also adds new weapons and new enemies including a boss battle. One final addition that Sigma Team made, due to popular demand from fans, is the inclusion of a tougher difficulty level selection at the beginning of the game.