Suggestions are always welcome.
-Tropical-
This would be hard to script, but, weather?
For example, it starts raining every now and then and becomes almost impossible to see. If it starts raining heavily on your way back to base, other groups can ambush you.
There can also be hurricanes, with the rarity of the geyser, that have such strong winds they throw you around, probably killing you.
For food you would have to fish and hunt local wildlife.
There could also be snakes that creep into your camp at night and bite you, sometimes they are poisonous. You don't die from the poison immediately, you constantly lose a tiny bit of health for five minutes until you die.
--Desert--
I don't have many ideas for this yet, but instead of heat you have water. You lose water most when the sun is high in the air and least at night.
