Infinite ammo would kill this game believe me. If you want to unleash firearm violence xD you have to max out every weapon's ammo before you finish the game so that you have it all for your +NewGame. I highly recommend maxing out the machine gun ammo (took me 3 runs to max it out) and going directly into the end of chapter 2 right before the bridge sequence where the cannival BBQ is going on. It is extremely satisfying to use the machine gun on all those haunted. Even more, that area is the perfect place to test weapons since there's like 3 or 4 waves of enemies attacking and there's enough space in the area to maneuver. Once you have disposed of them all, just load last check point again and again and you have yourself a little mini game right there to enjoy some shooting yay!