I'm planning my first RPG ever, and I need some ideas for a map based on oxygen. The main part of the story is you being in space with a limited air supply. There are bases with supplies, ability to mine, and many other things that I need to think of. It will be a two or four player RPG. I'm also trying to make it open ended. Btw it's in installation. I need your help to figure out more features.

Fires can deplete oxygen.

have gas or minerals represent the amount of oxygen u have and have it continually going down, then have some Gas tanks or w/e wen u go near give gas, wen u run outta gas (oxygen) u lose the game or somethin

Maybe if you run outta oxygen you can recieve damage (DDS) every second to finally kill you if you don't find more oxygen.

That sounds complicated, wouldn't be better if I just gave them 30 seconds if they ran out?

Lets say there are vespene tanks or something the like scattered throughout the map representing oxygen. You could treat them like items. Sorta like, if you know yu're gonna need some more oxygen, you can choose to use one of these to replenish you, or if you run out completely, it could replenish you automatically (think of fairies in The Legend Of Zelda).

Also, a nice feature would be, if you're dying, use your oxygen tank to turn yourself into a bomb and destroy everything around >:0.

Yes. Technically, if you could find a method to stay alive during the DDS period, you would gain extra 'breath' which doesn't make much sense. Physical damage =/= respiratory difficulty.

Zones could be designed that have airlocks and are pressurized. Quests could be built around these zones and the need to move outside of the zones to accomplish objectives and/or acquire items. Events could be designed where an airlocked zone is compromised and the player has to escape to another section and close the blast doors behind him or her. Constantly ordering the player's unit to move towards the breach would accomplish the vacuum effect of space. Also, the player should have a set time period before (even if they're not getting sucked out) all the air is sucked out of the zone and the player suffocates or dies from exposure to the extremes of space.

What you have so far seems promising - don't let it die.