The bags participate in two modes of TimeSplitters series: Capture the Bag and BagTag. In Capture the Bag, it serves to steal a bag from the other base (also the classic Capture the Flag). In BagTag, the players fight over who can hold the bag the longest. When the player carrying the bag dies, the bag is dropped on the floor until someone else picks up the bag.
There are four colors of the bag, yellow, red, blue, and green. These can vary depending on the game mode that you are playing. For example, in BagTag, the bag is red by default. In Capture the Bag, there are two bags, and they are both opposite colors. Only in Timesplitters 1 there is the bags for all 4 teams, Only red and blue are available in Timesplitters 2 and Timesplitters: Future Perfect.