there is a go-it-alone ending. Just like how each faction has a research tech that locks you into an ending, there is one for the Phoenix Project as well. Specifically it is the Virophage Injector tech.
After you have the tech there should be a mission to complete the game. I cannot give anything more concrete as I haven’t gotten to the endgame yet
Alongside doing the Antarctica mission, you have to research (I have the researches on a text file at home so names might not match perfectly):
kill a queen and research Pandoran citadel
Maybe an other research like “Yuggothian Receptacle”
If I have my research tree kind of correct you have both pre-requisites to make the PP end game research “Virophage Injector”
Doing the game without factions means lots of reverse engineering and stealing research for some extra goodies. Also means that you have to wait for the factions to do some researches rather than doing them yourself much much quicker.
I do think it’s possible. By the tech tree that I have drawn from my two play-through, the path to PP ending doesn’t need any faction research. You need to rescue havens though to get rid of one nest & one lair and have the corresponding researches available.
All factions do is give you “better” tools (like piercing, paralyzing, …). Tritons do wield some faction weapons that you can reverse engineer. And Synedrion “gives” you a 9th base.
Guess I’ll try next play-through… in fact I think I’ll pause my legendary one to try that, but it’ll take some time (family), and I’ll still be recruiting infiltrator and priests.
From my experience, you have to follow the PP scenario until you do the Antarctica mission.
In the mean time, you also have to research the various pandoran structures.
Then, it unlocks the ending for PP.
However, I haven’t done a campaign without being allied with all factions, so it’s difficult to know if I haven’t done a research with a faction that was a pre-requisite. So I really need to try, starting this evening.
I did the whole play-through while doing no faction mission and keeping them at 24 or under (of course I cheated to go this fast - by using the console with a mod on nexus for most of the missions but still doing some normally).
You don’t need to steal research either (at least in my play-through I could scan & go to Antarctica without it).
You basically have to follow the yellow stuff that is written in the top left corner. Easy !
If you want some spoilers, the research tree looks like that:
Atmospheric Analysis: see mist coverage
The Phoenix Archives: can have a hint on location of Phoenix bases
Oneiric Delirium Index: gives access to the DOOM tracker
Destroy Nest -> Pandoran Colonies: -
Destroy Lair -> Pandoran Lair: -
Destroy Citadel -> Pandoran Citadel: can scan for nests, lairs& citadels
With Oneiric Delirium Index & Pandoran Colonies:
Pandoran Capture and containment: can build containment chamber and build Neurazer
Siren Autopsy: some resources
Siren Vivisection: 10% damage increase
Pandoran Telepathic Nodule: some lore
Scylla Autopsy: some resources
Scylla Vivisection: 10% damage increase
Meanwhile we have the Symes story that we need to follow till the end:
after “Time Vault” mission, Antediluvian Protocivilization: soldiers 10% additional XP from missions and training
after “Antarctica” mission, Yuggothian Entity: know the enemy
After you have Pandoran Citadel, Yuggothian Entity, Pandoran Telepathic Nodule & Scylla Vivisection:
Yuggothian Receptacle: know what’s coming
Virophage Injector: END GAME FOR PHOENIX PROJECT
And of course, you have lots of reverse engineering to do (if you manage to find the weapons as loot). Capturing a Scylla with Neurazer is fun.
Something strange happened though. In lots of missions (rookie difficulty) I had very few Pandorans. Scavenging missions with 2 Arthrons and 2 Mindfraggers, a single Chiron or Scylla in a Haven defense, lairs or citadels with 3/4 enemies. I remembered my first rookie campaign as much more difficult.
I don’t know if it is due to the fact that I used the console to auto-win some missions that screwed the difficulty or if number of enemies gets bigger with your relation with factions.
Food for thoughts…
I never took out a lair, only a nest and citadels. I bet that’s the problem. The final research should be available if the immediately prior step has happened, but for some reason it is dependent on all the steps happening? Maybe.