Squad of mercenaries or some sort of military types are on an unexplained mission and start finding dead bodies and seeing weird shit so they hide inside an armoured personnel carrier and pretty much spend the rest of the movie being miserable in there.

hey cool
Grim and mildly trippy
but YUCK
Brain not liquified by profound ambiguity

First of all it's not a tank. Stop calling it a tank. It's an armoured personnel carrier. I assume they didn't use an actual tank because they wanted to have all the characters sitting inside facing each other and APC 432 doesn't sound as much like a movie anyone would want to watch, but calling this vehicle a tank is like calling a woolly mammoth a dinosaur in your movie about people trapped inside a woolly mammoth and expecting pedants to take it seriously. If you want to see a movie about guys really in tank check out The Beast of War, which is not horror and isn't that great but at least there's a
damn tank.

That aside, this is the kind of movie that I sort of enjoy while I'm watching and then promptly forget I ever saw until I notice the title again on my giant list of half finished rants and flash a microexpression of furrowed brow and pursed lips before forgetting again. See it's one of those movies that try to prey on our simian curiosity by not explaining anything and promising some sort of astonishing M. Knight Shyamalan reveal at the end. Problem is even Mr Knight Shyamalan usually doesn't pull it off and I end up feeling more bullshat than brainfucked.

That's sort of the case with today's movie. I don't really hate the ending, it's acceptable and could have been more if executed with stunning brilliance, but it's not, and I saw it coming halfway in, and (spoiler) turns out to be just the military industrial complex trying to create supersoldiers thing again. And while on that subject, seems like a waste of money at this point to me since guys with rifles don't win wars anymore anyway. Here at The Park R&D is focused on the weaponised monkey pox.

But like I said, it's not until the movie is completely over that one feels a bit ripped off
so it's an okay hour and a half of people having nightmarish hallucinations and claustrophobia inside an armoured personnel carrier . The soldier stereotypes are merely not likeable and there's horror stuff like gas mask monsters and messing with rotten corpses and one guy gets run over lengthwise by an armoured personnel carrier.

And to give what credit I can, the twist ending, while unimpressive, is set up in a way I haven't seen before. Basically the complete lack of exposition or explanation is itself meant to be a clue as to what's going on, but to know what I mean by that you'd have to watch a pretty average quasi war horror movie about a... okay to be fair the proper UK title of the movie is Belly of the Bulldog which is more suitably arsty and ambiguous and makes no mention of a tank.