From The TimeSplitters Wiki

One Shot Thrills One Shot Thrills is a group of Arcade League levels in Timesplitters 2. It is in the Elite League and consists of battles where you make one shot kills and die in one shot. They are listed below:

Babes in the Woods Mode: Shrink Silver: Jo-Beth Casey Playing as: Harry Tipper Level: Aztec This is a level where you fight against several Jo-Beth Caseys in shrink. The only weapon here is the Crossbow, which is suprisingly useful here. Tips Keep moving around. If you shrink too much, then restart. Reload when moving and shoot everybody you see. Just one hit will do it so don't go mad shooting crazy. If you die, it is okay. But always keep a crossbow in hand. If you are unarmed and surrounded by enemies then just punch, it will still only take one shot.

Double Bill Mode: Thief Silver: Beetleman Gold: The impersonator Playing as: Big Tony Level: Chasm This is a level where you are fighting against several Bettlemans and one impersonator. Theis level is very big so be careful. Tips Keep moving around. Don't fall behind and don;t forget to get all the coins that is rewuired in Thief. This level is pretty hard, but remember it is only one shots, so no need to use double shots with the Tactical 12 Guage and again, reload when possible.

Nikki Jinky Bricky Mode: Team Deathmatch Silver: Nikki Gold: Jinky Playing as Nikki Level: Chinese This is hard due to the brick, but always use the aim and you will do fine. Tips Try to kill fast. You can't punch so use the aim on the brick and don't be late when throwing. Don't throw wildly. Throw when you know you got them, but do it quick!