Options:

F1 - Inf.Health
F2 - Inf.Boost
F3 - Inf.Ammo
F4 - Inf.Grenades
F5 - Fast Kill
F6 - Inf.Resources

Notice:

First start game world then activate health, and boost cheats
First fire your weapon which uses ammo then activate ammo cheat
First throw an explosive then activate grenades cheat
First hit an enemy once then activate fast kill cheat
First open upgrade window then activate resources cheat then close window and open it again.