The cubes and tablets are deciphered soon after. Rather, the tablets are. They just also happen to contain a manual for the cubes on one tablet. The other has a brief explanation. Basically? Every 100,000 years, an apocalypse kicks in, wipes out the dominant species. A little while later, something has mysteriously replaced them. Wait 100,000 years, repeat. This was written by the previous species as a warning for the next one. Clearly, they did not make it, though they were rather more advanced (if physically less capable) and at least got as far as pattern recognition.
The cubes are a major gameplay mechanic. You have two uses for them. Storing stuff to summon, or absorption. To explain in a bit more detail, when something dies, you can finish it off with the cube, a rather weak weapon. Since you can see their health, this isn't too hard to time. To the layman (read: PC and NPCs), it would look like draining their souls. Sufficiently advanced technology and so on. In practice, it amounts to taking something similar to a DNA sample and passing it through a replicator once you get enough from the same creature. This is in turn used to gain aspects of that creature. Say you drain... well, a manticore? You could get the sting, the wings or the spine-firing (if you want the D&D version), or maybe special vision or something.
I figure it can be anything from upgrades to weapons to passive abilities. You wouldn't have guns (many, anyway), but you would eventually have ridiculously high jumps, extra arms, fire breath and whatever. I fully intend to explore the "by the way, you're not exactly human/whatever any more" side of this. Sure, it's necessary. At the same time... well, more and less than you used to be. The list of weapons will surely be stupidly large, so I guess the ability to switch out your list at certain locations would be good. Think Bioshock gene bank, sort of. Just so you don't need 50 keys for weapons or whatever. The other function? Rapidly reconstruct the creature you stored in there, with a cooldown. Basically, summon it to briefly fight for you, after which it falls apart. I know, moral implications, since it's fully sentient. Incidentally, this would probably be just another weapon.
Prior to the cubes, you're nothing special. Regular person, armoured, knows how to use a gun and maybe the odd melee weapon. It's only later that you go all mutant-y. The progression from interchangeable panicking gunslinger to a rather powerful but decidedly inhuman (or in-whatever your species is) mutant-thing is slow. You'll probably end up looking like the enemies, eventually. Called demons, by the way. Is it accurate? Not one bit. It is, however, an easy name that people quickly coin and latch on to.
Now that I've bored you, back to plot! Which is also boring. Only longer. I'll keep the rest to cliff notes, since I'm sure people here have a limit to their patience. Basically, in the place the directions point to, you find a member of the previous civilization. Alive, in the cryogenic sleep sense, and hidden away. Basically exists to be a guide. Bad news? He's not so sane any more. Helpful, but cryptic and doesn't remember much in any case. He realizes this, and sends you to other places for a bit of guidance.
Put the pieces of the puzzle together, and you'll find proof that the moon has popped up before when the apocalypse came about. Also? You have a couple months until what appears to be orbital bombardment wipes out the last survivors (of the dominant race, as far as you can tell. The bombardment is mostly on the cities, the rest is a tailored virus by the sound of it). Assuming all this stays on-schedule, of course.
So your guide gives a suggestion. Use some stuff he scrounged up, bring more parts to him, let him build something that allows you to reach the "moon". Not a ship as much as a teleporter of sorts. One-way, so he asks you to explore some of the obelisks first in case that's a better guess.
The obelisks turn out to be larger on the inside, partly since what you see is only the tip. It works rather like an iceberg. It's part lab (automated, run by machines), part factory for creating more of the demons. Part cryogenic warehouse, storing them in between apocalypse runs. You can decide to steal tech, blow them up, just leave, whatever.
In any case, obelisks are a red herring. Here's hoping the moon is not.
The protagonist is NOT disappointed. That's no moon, as they say. Rather, it is, albeit encrusted with piles of weapons, and equipped with means to send a virus or new lifeforms down to the planet. Whichever. You could probably use the latter to get back at this point... if you knew how to pilot it. You very definitely do not. Might as well show a TV remote to an amoeba.
There's also a portal. Takes you to a base, somewhere veeeeeeery far away. After a series of demon zergrushes and mandatory VERY tough boss fights. This includes the machine that appears to be in charge of making each new species AND the weapons system. Yes, you essentially kill both (on a localized scale) a ragnarok generator and the creator. Or spare them. After all, anyone's going to be a bit touchy about killing the thing that created their entire species.
After the teleporter? You end up in a control room with one person hooked up to any amount of life-support machines and so on. Sitting in a chair, basically defenseless. You can kill them, of course, but who else is going to give you answers?
The explanation, basically, is this. Your planet is wrapped up in a time field of sorts made by these people. Time passes far faster on the planet than in the rest of the world, meaning 100k years there are, in the rest of the world, a FAR more sensible timeframe. The goal is to make powerful biological weapons, more or less, on a planet these "engineers" found. By the way, these people? Humanity. They're responsible for it all, albeit in the far sci-fi future.
The process works like this. Make a species, drop it on the planet, possibly with tech. Wait. After 100k years on-planet, begin the apocalypse. Once the dust settles, take the few survivors, find what made them good DNA-wise and so forth, add this to the next species you make. Repeat the process. The process is complete when they become good enough to stop all this, as you just did. The problem, of course, is that you could only do so because of the cubes. The race at large is worthless, as they still got annihilated. The demons, by the way, are similar - pretty much just a chimeric mix of lots of previous experiments, weaponized.
The reason for all this stuff is a single creature. Something trapped in yet another planet, which has a reverse of the time field on your planet placed around it as a temporary containment measure. Yes, it slows the world inside down. Yes, the creature inside - basically your generic Lovecraftian eldritch horror - is eating away at it. You are the solution, something stronger than humanity (en masse, anyway, not alone) that can stop it. Hopefully.
Of course, there's only one person good enough for this. The person in the chair, who calls themselves the Architect, offers you a choice. One, submit. Get put in a containment cell, outfitted with a chip that makes potential rebellion impossible, get cloned a whole bunch of times (maybe with slight variations considering all the potential mutations you racked up by then) and used as an utterly loyal force to eradicate this threat. Hopefully.
Two, kill what amounts to the god of the entire world below. This will shut off the teleporter immediately and security will rush in, but hey, defiance. Three, leave. Leave and most likely die eventually to make way for the next species which, thanks to you, will be far improved. The choice is yours.
Basically, defy and kill your creator for what they did? Save the world from one of Cthulhu's relatives? Both? Walk away? You decide. Either way, sequel hook. Fairly sure publishers like those.
