Better Accuracy (Bullet goes where you aim), Faster projectile speed, Better camera (With default camera the crosshair is too close to the player), Options for more Health, Better painkillers, More Ammo, !(for camera mod to work, starting a new game is required)!
The rar files contain seperate folders for every mod, to install one of them, just copy the data folder to the games main directory(the one with the .exe...