Can I brainstorm with y’all?

I am designing a D20 game that will be a dungeon survival game. The characters wake up in individual rooms in a dungeon (they end up together as a party but may not know each other or even if the person is a PC or not) and have to survive from there. I would love to hear questions, comments, or concerns to help me fleshout the game

The base concept reminds me of Torchbearer, which is a dungeon-crawling OSR game that puts the focus on the dungeon as a hostile environment and the conservation/dwindling of resources. Might be a good source of mechanics/idea fodder.

In reply to NowhereMan (msg # 2):

Thank you! I will look that up.

Torchbearer is not d20, but based off of Burning Wheel (through the Mouse Guard RPG) and uses a d6 dice pool. It's a good game, and you might get some ideas from it, for sure.

The first thought I have upon reading your pitch, is what will drive the PCs to work together? Or is your game going to encourage PvP? Whether they're supposed to work against each other or together, either way could be fun. But the drive to play the way you expect the game to be played should exist.

In reply to DVUS (msg # 4):
Thank you for responding! When I have use this idea in the past I’ve never had a problem with the party not cooperating. However, I am going to let the players let me know if they want PVP or not and if they do not, they will just be told that they need to cooperate. Since this is played by post, if they want to go separate ways, I can just run more than one game.