Love the concept, but there's one thing I'm not sure about: If the players know that there will never be enough food for both of them, what's to stop them just trying to kill one another immediately?
Because the only way to get enough food for one person in time is for both of them to work together. Also, there will be certain puzzles (simple ones) that can only be passed with two people, mobs that can only be overcome with two guns at the ready, and a few other hazards that would be best faced with two players. A lot of the tension in the game is deciding when to help your friend for your own benefit, deciding when to hold out on them, and deciding when to outright betray them (Wow, that's pretty cynical). In the beginning there'll be enough food for the two to work together fairly well, but later on... Well, there's a bunch of ideas I have, but I'm still fleshing it out, seeing what'll work and what won't.
Couple of ways the game could potentially end:
a. One player kills another player while the current total food is equal to the food needed to survive. Win.
b. One player kills another player while the current total food collected is less than the food needed to survive the rest of the time; the game then determines how much food the living player would be able to collect on his own by calculating how many assets are available in the area, then determining if that player won or lost.
c. The same as b, except one of the players dies on his own as a result of monsters or weather or stupidity.
d. Both players die.
Here's a grid based building system that
was inspired by Under the Garden. The blue thingy on the right is a drill, for exploration into the cave and tunnel system underneath the surface of the planet.
Also, for those who are interested, I recently got a Twitter account. You can find the link in my signature.