Up to this point, Ive intentionally avoided big threads on how I think Thrive should play later stages. It’s energy that could be spent working on the current game, if people disagree with me it’s even more energy spent having arguments that won’t likely effect the game that gets developed, and if everyone thinks my ideas are great it puts pressure on future generations of developers to do something just because everyone kinda remembers that we agreed to do something.
But Deus encouraged me, and maybe things are moving faster, and frankly I’m not contributing much to Thrive right now anyway, so heck with it! The following is how I currently envision all the pieces of Thrive fitting together. I do think all of this is POSSIBLE to create, but it doesn’t nessicarily line up with what’s already been developed, and I don’t expect it to actually happen. If I’m still around to see later stages get worked on, I also expect I wouldn’t still agree with what I say here:
Also, I intentionally didn’t read iosononeon’s post before writing this, because this is a brain-dump, not a rebuttal. I assume we disagree, and I will find out how when I read that post.
Microbe Stage
I think it’s fitting that we’ve been stuck on microbe stage so long; to most players microbe stage would be a microcosm of the whole game, the encouragement to stick around for the rest, and the trial to “earn” the rest of the game. I envision a lot of players wanting to skip microbe (and probably multicellular) to get to the more charasmatic “real” animals, then feeling the experience is somehow “hollow” without starting early enough in the planetary history.
The observent player will notice that this stage serves a second purpose: defining the metabolisms of the main groups of life (which is too much detail to worry about in later stages). Never again is it as easy to adjust membranes and organelles as it is in these early eons, and the basic exchange rates of the cells present at the end of microbe stage serve as the base stats of life moving forward, providing a “seed” of sorts for what life on this particular planet is capable of. Try-hard players would use this, along with trying to time the jump to multicellular with the movement of tectonic plates and atmospheric changes, to meta-game the rest of the planet’s history. To normal people, microbe stage is tutorial island.
Multicellular stage
I would design multicellular stage to increasingly force the player to let go of control over individual cells. I made a video a while back about my experiments in cells making independent decisions in a multicellular organism, and as you grow larger you increasingly need to trust in parts of your body to do their job. Instead the player’s focus is on designing a layout of cells that work as a body, perhaps with things like propulsion limbs or a digestion area, and mentally bridge the gap from being a colony to a body (which is too much detail to worry about in later stages).
I would also limit how much you can really fine-tune cells, either drastically increasing MP costs to change things, or having a whole new menu of mutations that force you into the same basic blueprint of life. Maybe you can only add certain parts like flagella, toxin, cillia, or neurons, and internal parts just scale magnitude to match. The basic way life on your world metabolizes is locked in now. Sure hope you didn’t soft-lock yourself with a microbe that doesn’t work multicellularly 
macroscopic stage
At this point, the species is too big to count cells, and we’ve established that the player is smart enough to know how an animal’s body works, so it’s time to actually get to be an alien! The player is now one entity again, and it’s a wiggly organism that always swims in water. In my “wildest dreams” game there is no aware stage, and with it no need to ever have a spine, but in my practical dream, macroscopic is limited to free-swimming sea life specifically because we aren’t trying to procedurally animate every imaginable invertebrate, just jellyfish and worms and sea bugs. Stubborn players will try to explore these possibilities as long as possible, but most will give in to the temptation of all the “requires spine” parts and move on to more complex, but more restricted, life forms.
I don’t really know what makes this stage special. The environment is changing, the competition for survival intense, but that’s true of the stage before and after. This is the one stage that doesn’t have a level of detail established that all later stages take for granted. If anything this might just be a technical stepping stone, and a slight tutorial for playing in 3D before the player starts walking and invalidates half of the lessons learned.
Aware Stage
Aware is tricky in my eyes, because it’s kind of the culmination of the game, and kind of where two different kinds of progression happen. On the one hand, the “point” is to get more brains and become sentient. That said, the move to land is really essential for that. Forbidden topics aside, being an underwater tribe that can’t go beyond the stone age is a silly dead end, and not something I would invest resources in developing. And besides, land is a fascinating new environment to explore, and something to do.
All THAT said, I could see this stage being a great filter. If we do our job right in making a game about adapting to environments instead of sandboxing your dream species to the top, a lot of species might just not find a natural reason to get too smart, and in my dream game we wouldn’t discourage that. But the path to paying taxes is up above the waves, and in a bigger brain, and I would trust determined players to try to find a way to get there. And I would actually let it be difficult, and not that viable in some games. Encourage exploring the biosphere of the world, (maybe even jumping species some) and getting to know what it means to be a living thing on this planet (which is too much detail to worry about in later stages)
Awakening stage
This is actually the stage I’m most excited about in my dream version of Thrive, but probably not one I would enjoy very much if we ever actually get here. To me, Awakening stage isn’t about working your way up the tech tree in a survival game. Not only does Minecraft already exist, but the player has already survived in the environment, as a dumb (and often solitary) animal. Instead, Awakening is about figuring out YOUR species does civilization on THIS world (which is too much detail to worry about in later stages)
Awaking stage would focus less on getting the ingredients to make fire and more about figuring out what to cook and how you’re supposed to cook it, as well as which members of the tribe eat first and why. I would actually add a full on myth editor, where you can craft stories about species in your environment and encourage your tribe (which you partially control) to act in a certain way. As your population grows, individual control gets increasingly impractical and you need to develop a more and more complex social structure to keep (most) people useful. Eventually you get so complex, and capable, that you begin to resemble…a society
This stage both serves to provide some unique character to your species as a whole, and puts you on a “team” for the next two stages. Some things you do effect how sentience works world-wide, while others are unique to you in the next stage.
Society Stage
Alright, time to burn the rest of the goodwill I have with this team: I think Thrive should include racism. I think Industrial stage should be mostly about racism, and I think that Society stage should be racist.
By society stage, it’s not a mystery which species is going to dominate the planet. Maybe you will wipe yourselves out with doomsday weapons before going to space, but it’s a while before anyone even invents those. So what’s the stakes in all these ancient empires? The same as in the microbe to aware stage: to see if your unique take on life survives to the next level.
In society stage you start as one city-state, belonging to a culture group currently unique to you. As you expand, rouge colonies, and rebel states are nearly inevitable, but not entirely bad: any society that splits from you shares your culture group. Depending on how advanced culture mechanics get there may be some drift, from a lineage standpoint they are still tied to the parent society, with multi-culture-group societies probably coming in as a late society/early industrial development.
When your country falls or loses to a revolution, you may pick any other from your culture group to play on as, excluding the one that took you down. There is still motivation to get and stay big (the AI countries will probably suck), but there’s also a lot of reason to look after other countries that are like you against distant barbarians. AI civilizations have a similar in-group bias, but are not particularly interested in moving up the tech tree for its own sake, or tying to reach the next stage. Moving the species into enlightenment is mostly something the player has to do, if the player can survive.
In any realistic game about history, there’s no way a country at the start of civilization is there at the advent of the steam engine, and I would tune society stage similarly, where holding a country together against decadence is a snowballing effort, and the real goal of metagamers in early society is to just make a big enough empire to serve as buffer against other culture groups while building up the next country to get a little more advancement. And, of course, to build a lot of stories along the way.
I would also not try to center society stage around a city, and go turn based. Y’all are welcome to amaze me with your game technology, but I just don’t see how you do a civilization like the British empire justice in real time, while only seeing London. In addition, I would have society stage have the smoothest transition out, which a few key techs adding new game mechanics, with the most important ones being the “doomsday techs” (pollution, nukes, maybe a cool bioweapon thing that didn’t happen in our timeline but happens on a third of worlds or something). I would also have this be the only stage where an AI can outpace you, under the soft understanding that if you stick around in society stage while someone else invents the modern age, you will probably not stick around too long. If someone in your culture group is doing the domination, congrats on (eventually, hopefully) getting a free boost to the next stage. If it wasn’t, then game over; somebody else gets to write the story of your world’s society, and you get to be an indigenous culture for the museums.
Industrial Stage
Now that you’ve clawed your way to survival, it’s time to clean up the mess you made getting here! I would keep the culture group mechanic at this stage to avoid confusing players (and because it’s possible to come into industrial stage as a tiny nation that is about to die), but at this point timetables are shorter, and you’re likely to come out of industrial stage as the same country you came in as. The real challenge isn’t making sure someone like you survives, but that the species as a whole makes it to space without blowing up. Previous history has provided a lot of time for biases and grudges, once again no AI nation is trying to reach the next stage like you are, and it’s only a matter of time before everyone develops a way of destroying your world, even if only through a slow death by greenhouse gasses (and I would play up, and even exaggerate, the “doomsday” power of pollution and nukes, because that’s more fun). Depending on your situation and how you got this far, you will need to do some combination of convincing nations to put aside differences and work together, and forcing unruly peoples to get in line and adapt to a future that keeps your species alive.
This is what I meant by being about racism. A problem I have with most CIV-type games (and I admit I haven’t played enough to have a truely informed opinion) is that there’s no concept of advancement as a society other than conquering the world. Sure, sometimes you conquer the world through culture, or by developing technology that totally isn’t for killing people but somehow means you win, or just making a really big statue, but it’s still conquering the world. I think that a game about civilization, particularly a game about civilization as an extension to evolution, should be about aligning your world, maybe “unifying” it. Not nessicarily under you, but enough that people can agree on not doing stuff to kill each other, even when that might put people in a better position to kill you. Destroying all other cultures in one way to help with this, but so might merging all culture groups until everyone is on the same “team”, or even choosing to take second-fiddle to a bigger nation that you’ve come to trust. I’ve always hated 4X games where I try to play “nice”, just to realize I have to stab my nice ally in the back before they make too many ice cream cones and conquer the galaxy through ice cream victory condition.
In my dream Thrive, there’s also a backpath out of Industrial stage: build a sleeper ship out of the solar system. This ends Industrial immediately, and you begin space as a lost colony, maybe to find out what happened to your parent planet later. It’s a penalized start to the next stage, but it might be a lot easier than trying to fix a world that’s gotten really messed up.
Space Stage
I don’t really know what Space stage is about, but I don’t really think it needs to. I think it’s agreed that we are going with a FTL space stage, which means this is already fantasy (fight me), and frankly we aren’t covering much of any real science here. I would imagine this is the “silliest” stage, with a random smattering of exploring other runs of auto-evo, conquering the galaxy, and society stage all over again.
Building an ascension gate is either something every space empire wants, and is a tight constraint to keep you from goofing off too much (or getting bored), or is something only you feel motivation to do, if you do, and serves as a way to end space stage when your done. In the mean time, fun sci-fi threats create some drama, but I don’t imagine much deep history here. unlike in previous stages where everything is telling the story of your planet, if you lose in space stage (particularly if you meet a fate where you are annihilated) your previous game doesn’t really matter anymore. Even if things go alright, as space empires rise and fall, and species mix and mingle, the story of the galaxy increasingly stops being about what happened on your planet, and more about what a bunch of randomly generated planets do. Maybe that’s worth it, and Space stage is just a stellaris-like sandbox where you forget the rest of your game, but my guess it’s more Masters of Orion: a short scramble for each species, all new to the stars, get a mastery of things before getting wrecked by somebody else.
Accention Stage
Accention stage isn’t a stage. It’s Space stage with cheats on, mixed with some freeplay modes of other stages. I’m not complaining about that; it sounds like a nice break for both the players and developers. Shame we’ll probably never get there 
Feel free to discuss, but I mostly consider all of the above to be pure fan fiction, and not particularly important compared to anything posted by a fan on the community forum. I’m mostly curious what I think about it in a few more years time. I have the strongest opinions on Multicellular of course, and I’m sure I’ll enter those debates in good time, as that stage looms ever closer.