From Wikipedia
TimeSplitters is a 2000 first-person shooter developed by Free Radical Design and published by Eidos, and the first game in the TimeSplitters series. It was released 26 October 2000 as a PlayStation 2 launch game. The game revolves around the concept of travelling through time in a story mode spanning 100 years. The game features a story mode, arcade mode, unlockable challenge mode, and map maker.
Story mode
The game's story mode can be played alone or cooperatively with one additional player. Taking place at nine fictional locations between 1935 and 2035, the story follows 18 characters' individual attempts at defeating their own foes and the TimeSplitters with whom they have sided. In each level, the player can choose from one of two characters specific to each mission, and must kill enemies as they move through the level to retrieve an object and then carry that object to the exit portal. After a player picks up the object, TimeSplitters, evil mutant creatures, spawn throughout the level and attack the player.
Arcade mode
In this mode, up to four players and ten bots can compete individually, or in up to four different teams in certain modes. The players can set choose from characters, levels, and weapons that have been unlocked by completing story mode and challenge mode missions.