I'm afraid you won't get many reasonable answers for that particular topic, because very few people (if any) have tried something like that. In fact, the only person I can recall doing something like this is Vandermeer, but I don't know how far he has come with his campaign.
I randomly found this topic when doing a search in the forum. It's really late, but I comment:
OT about this swarm game:
It all worked as intended, and I have played quite a bit (maybe 80 years) beyond the documented part, fighting successfully against two common spoilers, and with just as much drama to keep it interesting. However, I had lost all my documenting screenshots, and all the former photoshop files and the assembled art material while stupidly shift-selecting some files on my desktop that I wanted to delete. I failed to notice that this selects horizontally before vertical, and missed having my working folder of this game, and another 300mb work project of mine moved to garbage, and later also deleted. I only noticed a couple days later, and by then it was too late for any emergency recovery.
...But!: A couple months later, I was desperate, because that other project's lost work was really hurtful, so I researched randomly for file recovery, and amazingly found beyond the hundreds of people confirming that such deletes are of course lost, one person who mentioned that the fantastic Windows 7 keeps complete compressed copies of your desktop stored away somewhere! Lucky me for having current projects on desktop always, because there I found all my lost work and also the Zenit folder.
...So the only thing that held me back from then on was that I had lost contact with the game and narrative over so long. I tried to read back into it, but it was cumbersome to get the feeling for it again, especially after having an interesting new Aurora game running already. I may do it at one point though. Currently there are enough screens for 3-6 posts still waiting in line, and I successfully tested that I can still play the save too.
..For salvage: A salvage based game is totally doable, and since I tested that with the Swarm game there, I have switched to play all my Aurora games in a mixture from now on, where I allow myself to research to a certain tech level, and must then salvage the rest to proceed. I think that makes the game more exciting, as otherwise salvage is just a tiny bonus compared to your powerful research, and the only thing really giving you something sometimes is conquering an NPR. ...But even that is just a boost, while when you have this as your
only way to advance, you are really looking forward to conquest.
You need some crucial starting techs though, which is mostly some power factor (minimum x2 researched I think), because only then will your TL1 missiles be able to catch most enemies, and it will still be an extreme chase.(and you better have overwhelming mass domination, or else..)
Of course, before TL1 is just impossible. You have no weapons, your missile engines can't even catch civilian ships... nonsense. Otherwise, you can work it out, unless going up against a certain invader, but those are too rare to strategize for until it happens.
The last game I started also has a limit for TL3 for engines, so that is Ion, but I am free to research all fusion tech once I get access to a working Stellerator somehow. Then the same with the first antimatter plant should I get there, which I will have to salvage or loot. Most other leveled techs can go 2 levels above current engine tech, and things like power factor, stealth techs, jump engine miniaturization and weapon caliber are not limited at all.
I freely change these limits from game to game though, and had magneto plasma or magnetic fusion in games before.