Play and beat the game on Veteran Mode, then it will ask if you want to switch to survival mode. Select yes and it will switch to Survival Mode.

Complete the game on "Veteran Mode". Then it will aks you if you want to survival mode, ofcourse you select "yes" then.

Unlimited Ammo - Beat the game on the Green Difficulty



Unlimited Grenades - Beat the game on the Veteran Diffculty



Unlimited Health - Beat the game on the Hardened Difficulty