From The TimeSplitters Wiki

Flame Tag is an Arcade game mode in which one player starts off as "it" and tries to tag the other players. The player who's "it" is on fire, thus the name Flame Tag.

Aim

The aim of flame tag is to be the person who was it the shortest time. The one who is it is easily recognizable because they are on fire (NOTE: They are not damaged by the fire, although they can be damaged by fire from weapons such as the Flamethrower. A human player never starts out as being it, although you can spawn very close to the person who's it. You should play with a time limit, otherwise the game won't end, as the winner is decided by who was it the shortest time out of a time limit.

Recommendations

Similarly to Virus, create a weapon set with no weapons, so that you can't simply shoot the person who's it if they come toward you (otherwise it would be too easy). However, if you like shooting at everything that moves, weapons are good. Although selecting a map with lots of dead ends is perfect for this type of game, it may also prove to be very frustrating. A map where you can never truely be stuck can be fun as well, because then, incase you do get tagged, it's harder to tag others. All in all, play according to your tastes.