Quantum Theory, (known in Japan as クウォンタム セオリー) is a third-person shooter video game for the PlayStation 3 and Xbox 360. It is developed by Team Tachyon and published by Tecmo. The game was released in September 2010.
The game centers on two characters named Syd and Filena who must fight through a "living tower". The game features a cover system that constantly adds and removes cover.
The game is a third-person shooter incorporating a cover system. Players can fire their weapon from the hip, aim down the weapon sight for precision, or blindfire from cover. Enemies explode upon death and a successful headshot is rewarded by a slow motion close up view of the head exploding. Syd can throw Filena as a projectile weapon. Syd can use his guns as melee weapons. Syd's initial melee attack can also result in a follow up attack by Filena. Some levels feature environments that can change dynamically, including moving platforms that Syd must hang on to or jump off. Bosses make appearances throughout the campaign, requiring the player to identify and target their weak points.
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