Trainer options
F1 - Infinite Health
F2 - Infinite Syringe
F3 - Fast Kill
F4 - Infinite Weapon Durability
F5 - Prevent Knock Down
F6 - Infinite Combo Timer

Notice:
First start game world then activate health and syringes cheats
First hit an enemy or get hit by an enemy once then activate fast kill cheat
First pick up a weapon then activate durability cheat
First hit an enemy once then activate combo timer cheat