One of the main themes of From the Ashes will be Legacy. The game takes place in a world living with the consequences of the actions of those long since passed, and the ultimate purpose of the game is to transcend mere survival and leave something behind when they go.
It's a game where the only hope lies in the inheritance you build for future generations, and I think that sets it apart from other games that I've played. The PCs shouldn't be in it for the gold and the glory, because those things are literally ephemeral. From the time the game starts, the grim reaper sits on their shoulders, tapping it's finger on it's watch, reminding them that all the wealth and power they gather, all the friends they make, all the enemies they slay - none of this will matter when their own time comes.
Death becomes, rather than a foe to be conquered, a reality to be accepted.
The tension between the aspirations of the characters and the knowledge of their impending demise can offer some truly unique opportunities for roleplaying. Rather than going the gonzo, bears with hats and muscle magazines direction of Gamma World, I'd like to use the setting as an opportunity to see how a civilization can develop when it is severed from it's past. The Pure Strain Humans (gonna need to come up with a new name there) are going to be looking to find a way to pick back up where their ancestors left off, while the animals may have very different ideas about that, and the plants? Who the hell knows what they're thinking.
I remember playing the Torg RPG way back when, which uses a set of noncollectible cards called the Drama Deck. These cards allowed the PCs to assume limited narrative control over the story - they could play a card to introduce an arch-enemy, or a romantic liaison, things like that. There was one card in particular that stuck in my mind all these years, the Martyr card. A player coud use this card to change the outcome of any decision that the GM made. The catch? Your character had to sacrifice their life to do so.
At the time, I couldn't wrap my head around the idea - the whole point of playing the game was character advancement! Being the munchkiny little power gamer that I was, I decided that was a card I would encourage others to play.
Looking back on it, I see it for it's brilliance, especially considering their design goal was to make a "cinematic" rpg. Playing that card was the ultimate acknowledgement of the power of the story the GM was telling - the player wanted the story to reach a successful conclusion badly enough that they were willing to sacrifice their character to see it happen.
Of course, they probably just rolled up a new character and kept going, but I like to imagine differently. I like to imagine the player getting up from the table and walking slowly to the door like a latter day Lawrence Oates and disappearing into the night, never to return.
Or at least going to get pizza for the group.