I agree gamma is an exploit, however shades of grey on clear nights is needed to add an element of realism. It is currently too dark outside. It should be pitch black in rooms with no windows, and adjusted depending on the amount of available light able to enter the room. Torch light needs a fair bit of adjustment to make it useful.

A little balance is needed. A vital statistics HUD or similar should monitor and display energy, hydration and fatigue and would go a long way to explaining why you need to eat, drink and rest. Eg. I can run for 20 mins without needing to eat strait away, but i'd damn sure need at least 500mls of water after running for that long. As far a filling your stomach, you shouldn't have to! The foods should have an energy rating. Calories in vs calories out... A big can of tuna should be plenty to keep you going for at least 4hrs.