Hidden Invasion was published as a Playstation 2 game; a GameCube version was also announced but was later canceled.
Players are given the option of playing as either one of two playable characters in single player or playing as both in multi-player. The two playable characters possess different stats and abilities allowing for multiple strategies. Players venture through multiple levels. The camera is set allowing the player to see only an area of a level. Once the player leaves an area, the camera switches to the camera in the new area.
In the year 2027, one or two members of the Shadowforce Team is sent to assassinate the leader of a "terrorist" organization who has taken a building hostage in Alpha City. After disarming bombs and the defeating the terrorist boss, the agent is attacked by an unknown creature. When the Shadowforce agent recovers, a surviving "terrorist" explains a conspiracy in which aliens are attempting to take over Earth. The agent must then defeat the invading aliens.
Source: Wikipedia, "Hidden Invasion", available under the CC-BY-SA License.