What themes do you see possible in the refusal to accept death as a limit? I'm experimenting with a bunch of ideas around the notion that, in a timeless sense, there is meaning and purpose to life despite the fact that it is finite. In opposition to this idea, I have some characters, a few cultures and even a powerful civilization that will do anything to stay alive. I see themes as being able to be turned into interesting gameplay scenarios. A couple I can imagine: Life is so important that you'll do anything to stay alive, even if you can't recognize yourself in the end. -or- If longevity can only be acheived by the suffering or death of others, would you choose longevity or would you accept death? (The last I'd like to use as the backstory theme for the main heavies in the game world, implying that they chose longevity at the expense of all of life itself.) Any others? Any ideas on how to really bring these themes to the foreground and make them something that the player thinks about? Is this even something you think a game could make a player think about?

You would have to feel real attachment to your character and others. This has been attempted, but rarely works well.

I like how immortality is a curse in Gulliver's Travels. Some people are born with a mark that shows they are immortal, however immortality still means your body ages. Immortals become senile and weak , and the family members consider them dead after a few some time. Theme is actually an immortal looking for death, not because he is tired of life but because he does not want to be trapped in his body unable to enjoy life forever. The Immortal must find a "cure" for his immortality while he is still able to.

Wavinator,

If you haven't done so in the past, you can read "Use of Weapons" by Iain M. Banks for a twisted example of a personal drive to stay alive. Another book by the same author worth researching is "Consider Phlebas". Both have remarkably developed characters; it is the characters that make the difference. Also, all "The Culture" books by Banks give nice account of a powerful civilization where individual members enjoy very long lifespans.

Undoubtedly, with due amount of thought put into developing the personal/racial/civilizational drives in your game's plot, this can be done.
For a character, you can use personal motivation or some kind of moral imperative. A civilization may be driven by understanding that it is on the verge of a crisis - think, for example, a state's growing needs for oil that contradict interests of many other states.

Whatever you do, Diton9000 put it right, the player has to develop attachment.
I'd say, set a goal that in the context of your universe would seem important enough to become the central theme (drive) of a character's/civilization's existence. Develop that theme, see where it gets you.

P.S. In terms of plots, space isn't very different from Earth, so you surely can draw inspiration here. ;-)

I can tell you themes that have seemed to have "played" to greater or lesser extents. Cheating death by technology is as old as frankenstein. Cheating death by heroism is as old as greek mythology. Cheating death by magic is as old as alchemy and was well posited as a plot point in EPIII: ROTS

Real world examples are the suspension of death by freezing to absolute zero, such as Walt Disney did with his earthly remains. This theme has been attempted and hammered for a long time as a result of our intrinsic dissatisfaction with the fact we don't live forever.

Alternatively, a different perspective was introduced by Bladerunner. Be at peace with the fact you are gonna die, and revel as you live. The immortality view, as a plot element is going to be a tricky one to deal with, because of it's mythic intangibility. Other writers, not prefering to deal with it because there are only so many plausible ways to go without hitting a sour note in the mind of believeability in the audience, go for the comfort zone approach, skirt the issue entirely, and just give characters (at least the alien ones) extremely long life spans. The ultimate treatment of the denials we don't want to address is of course, "and they lived happily ever after."

Modernly, we've got genetic engineering, which is well treated in science fiction by this writing. As the new kid on the block (with the exception of Frankenstein, which was genetic engineering of the speculative kind priorto the actual existance of real genetic engineering) I think this is clearly the most plausible candidate. It encountered, and overcame, tremendous resistance. Remember when all the religious right was screaming about how science did not have the right to play god until they cured liver cancer? It suddenly became quiet. Good indication of how faith succumbs to greed everytime.

If I were to treat the subject of immortality in my work, I would make it more matter of fact in approach, and not bank on it's impact value dramatically, given the numerous treatments it has already recieved, the perceptual low marvel factor it has as a result of the 'oh yeah' factor of audiences. Dramatically, were I to live forever, I would sure want myself as a character to be doing some pretty amazing things. However, saving the universe over and over is pretty well hackneyed as well as a dramaforme. I see the new drama as being one of delving into the way we are in the here and now. It seems to be more and more popular these days as we mature as a contemporary culture to solve what is in front of us here and now, and seems a more palateable agenda considering science is pretty much taking care of itself. Wonderous new things to make life better are regular press releases these days, and not just blatant false advertising claims anymore. People who think that real progress is difficult are realizing that this is only because of people and their perceptions for the most part.

Like George Lucas said the other night, "We just barely got out of the caves. The next two or three hundred thousand years are going to be incredible." Btw, on the scoop side, a lady I know, her mom pulls permits for George. He's going to focus on documentaries from now on and fine art, and the Presidio is going to become the major location for his stuff now.

Adventuredesign