From The TimeSplitters Wiki

Big Game Hunt
IMAGE NEEDED
Game	TS: FP
League	Amateur League
Section	One Gun Fun
Mode	Team Deathmatch
Map	Siberia
Character	Leonid
Enemies Encountered	The Deerhaunter x8
Rewards	Vlad the Installer
Medal Requirements	?

Big Game Hunt is the second Arcade League challenge in TimeSplitters Future Perfect, and can be tough if you don't know what you're doing.

Strategy

Since you need a high number of kills in a fairly short amount of time armed only with the Sniper Rifle, it is suggested that you use a different tactic. Use your Radar and follow the purple arrow to the Vehicle. Now go run over the Deerhaunters. They inside and on top of the dam, but with your radar you will be able to see the direction where they come from, which is the same for all of them (they won't circle around or anything). Using this strategy, it's easy to get a gold and even a platinum.