From The TimeSplitters Wiki

Another Health game. Instead of collecting health and armor like you do in most other modes, in this mode, the only way to revive health is to attack the other players. Hence the name, "Leech". It has similar rules as Deathmatch.

Objective

Kill other players while gaining health from shooting your opponent. First to the score limit or has the most points after time runs out wins. ===Restrictions