So I just completed the game, with a moment of sheer badassery. I'd started getting into the habit of save scumming, which I tend to do in x-com games, and others... But I wanted to break out of the habit, so I ran the final battle without saving, despite how bad it got. So I have a squad of 9 guys (was 10 but one died) who are all at least squadie, a few of them have some rank (it's irritating how rank is based on how many other people there are). Three of them are decent psychics. so I fill that squad out with 7 other guys, so I'm to 16 guys, since equipment space is actually fairly tight, I give everyone (except the psykers and one guy with a just blaster bomb launcher + ammo) one heavy plasma gun (with only one clip since I doubt they'd run out anyway), a smoke grenade and an alien grenade, the psychers get the grenades a mind probe and the psychic thingemejig (what was it called?). Everyone has flying suits except the psykers who wear personal armour so I can tell them apart when equping them. The first few rounds of the mission go well, I take down about 5 or 6 sectoids without a casualty, despite some close calls. Then 5 or 6 more come along, and the psychic mind control manages to take over one of the rookies, who shoots a guy in the back, me not feeling in a forgiving mood shoot him as well. A blaster bomb also manages to take out three guys, at which point I find the exit and opt to run for it under cover of smoke with everyone I've got. 9 guys make it to the exit, 4 of them are rookies and 2 of them are psykers.
When I get to the other side everyone only has the weapon they were carrying due to the game being bugged. One poor guy doesn't have anything at all, They're split into two entrances, one of which contains two soldiers and a psyker, the other is 4 soldiers, another psyker and the unarmed guy in a flight suit. I keep the psykers and the unarmed guy in their spawns, when the 4 soldiers go down they immediately see a sectopod. Now I should mention the guy who popped up with no weapon was actually carrying the blaster bombs I planned to use should I run into one of these... oh well, I roll out the firing brigade and take down the septopod relatively easily, taking only one casualty from the return fire... Then I manage to pop one guy around a corner and take out a chrysalid. From there things get progressively worse, one of the 4 guys gets mind controlled shoots the guy he's next to, then heads up the lift into the spawn, where he continues to be mind controlled and shoots the unarmed guy... but mysteriously leaves the psyker alone... At this point I decided I'd be better off having everyone split up and hope for the best rather than shooting each other to death. Despite the confused hassle, mostly it's just two soldiers who keep getting mind controlled and panicked, so I leave them to it and have all the other soldiers search out, eventually they find a likely looking place, and I start to converge on there... except now everyone else is suffering panic attacks too, and one of the soldiers got shot by another again, and one other soldier started getting mind controlled... So now there's only one soldier who isn't clinically insane... So I send her up over to the objective, she kills two ethereals, moves up there... and discovers and alien museum... god damn it... so I look around and notice another door, and start sending her over there, and I notice one of my psykers has a clear shot for it, so I get her to drop her mind probe and grab a heavy plasma from one of the soldiers that got shot in the back. And she starts making her way there...
So the psyker is making her way over when one of the crazed soldiers comes out from a side corridor and shoots her in the face... and she survives, despite having only personal armour, but she has only a small nub of health left... and if he doesn't kill her, she's probably going to bleed to death. So soldier girl now no longer being able to count on backup, moves up to the lift, shoots an ethereal just above her and moves up to take a look, there's 4 more ethereals around a pulsating object that has to be the brain, I realize they're probably the ones doing all the mind control, and that they're probably all leaders, I remember the other psyker that's still safe in the other spawn, so I have him probe one of them figuring I wouldn't be able to control one of them anyway, and he discovers it's a commander, I have him probe another one and it's a commander too... So I have soldier girl auto shoot another one then move back dow- ... only thanks to my idiocy she's actually just run out of TU, so now she's exposed to three ethereal commanders... And I'm completely doomed, so I go and take another look at the psyker who's standing there bleeding to death in front of the soldier who just shot her, I've pretty much given up on the mission at this point, I fiddle around looking at one or two of the guys who have dropped their weapons and are sitting around cowering in corners. Then I notice that psyker girl still has her psy-amp in her backpack, so I take that out, and she's got 49 TU left, so she can only do one mind control attempt before she dies, so I go back over and make an attempt on one of the commanders but I've never even been able to control a leader let alone a commander... and yet it works, he shoots the other two down, and give soldier girl her oppertunity to shoot him, then gun down the brain... Victory is mine, it is an uninvited, yet not unwelcome guest.
EDIT: Yay for gigantic wall of text.