When I walked into the E3 demo room for Metro 2033 sequel Last Light, I was immediately presented with a small, thin military-green bag. Inside it, I found an actual, factual gas mask – sturdy yet pliable, and reeking of fresh-off-the-assembly-line rubber. It might seem like a curious object to take home from a gaming convention, but given the events that unfolded during Last Light’s demo, I can’t think of anything more fitting. So what follows is the story of a videogame. And also a gas mask.

After a blinding flash of sunlight nearly knocked Artyom flat, thunder crashed and lighting tore open a cloud-eclipsed sky. Rain drops began to pound on his gas mask – like bullet-quick pieces of gravel pinging off a car windshield. Then, one by one, they drizzled down it, blurring mournfully serene remains of buildings and struggling-to-survive grass tufts into a mess of gray and green. So our presenter made Artyom do something that – to my knowledge – no game character’s ever done before: he, you know, wiped it off.

I know what you’re thinking: Hallelujah, this will change the way we play shooters forever, and it’s not the Citizen Kane of gaming because Citizen Kane is – retroactively – the film equivalent of this mask-wiping masterpiece. Sarcasm aside, no, it doesn’t sound like much on paper. But it’s all at once indicative of Metro’s focus on putting you in Artyom’s eerily silent shoes and a brilliant mechanic in its own right. This could very well end up being a shooter in which the thing you do most isn’t shooting things; it’s wiping your face. Mundane? From a conceptual standpoint, perhaps, but the E3 demo gave no indication of it.

So Artyom and his presumed dead (at least, after the events of Metro 2033) companion, Pavel, marched on, taking shelter from the downpour in a total trainwreck of a train tunnel. In its nearly pitch black depths, they encountered another traditional gaming trope: a handy, dandy dead body – aka, “Hooray, treasure!” Disturbing its eternal slumber, however, yielded no loot – well, except for giant mutant spider creatures, because of course it did.

Artyom, though, isn’t Richard Cobbett, so he nonchalantly crushed one of the headcrab-wannabes as it skittered across his mask. As you might expect, our presenter immediately reached up and wiped away the resulting uranium-green blood smear, because ewwwwwww. Apparently fearing nothing – perhaps because, you know, genocide and all – Artyom then wandered off alone down a random hallway. He passed another corpse, at which point its band of rot-borne flies migrated to the mask’s surface, lingering and squirming about. In both cases, Metro’s world felt alive – but not in a pristine, robotically scheduled Skyrim sort of way. It’s a dirty, dust-and-grime-coated mess, and it doesn’t particularly care that you’re buzzing around on its surface.

However, the gas mask really shined (by which I mean “got completely caked in every irradiated goo imaginable aside from Mountain Dew”) in combat, of all places. Artyom hit the post-apocalyptic jackpot in the form of a loaded shotgun, but was immediately pinned to the ground by what can only be described as a giant ape rat – mostly because I don’t know what it was actually called. Jagged rows of teeth gnashing inches away from Artyom’s neck, its breath fogged up the mask as limbs of all shapes and ape-rat-ness flailed in mortal panic. But then – agonizing hour-seconds later – Artyom found his range. Blood erupted in suitably volcanic fashion, and the gas mask had front-row seats to the sloppy spectacle.

Pavel, meanwhile, actually reacted when he noticed Artyom – now probably wishing for a pair of windshield wipers – scrubbing away heaping globs of gore. “You’re covered in blood!” he exclaimed – though he seemed perplexingly unconcerned about whose blood it might be. Again, though, this place is a mess, and you’re certainly not moving through it in some hermetically sealed bubble. Games like Mirror’s Edge really did a convincing job of giving players a body within a game world. Metro: Last Light made me really, really want to bathe it.

Those bits, however, didn’t hold a candle to a down-with-the-ship last stand against a goddamn army of ape rats. After a truly unsettling supernatural vision in which Artyom witnessed – with his own eyes – an intensely gruesome flashback to a downed plane’s final moments (the crew got shredded to bits by glass as they went down over a mushroom-cloud-covered Moscow), he and Pavel stumbled back outside for a breather. Instead, they got 50 or so ape rats. Eventually, the pair ended up cornered at the bottom of a metro stairwell, and the disease-infested creatures started pouring in. Artyom and Pavel unloaded every round of ammo they had. Whirs of teeth, claw, and bristly fur, meanwhile, lunged through the air. It was total madness.

Eventually, I lost track of whose blood was even on Artyom’s mask. Was it his? A mutant’s? Pavel’s? All of the above? And all the while, Artyom had to choose between wasting precious seconds to wipe it off or essentially being blinded. It struck a perfect balance between overwhelming intensity and survival-horror vulnerability mid-combat. Battle, of course, isn’t a pretty thing. There’s copious amounts of blood, sweat, and tears. Last Light’s the first game I can think of to really take that literally.

Happily, at the last possible second, a hatch opened behind Artyom and Pavel to reveal two heavily armored soldiers with flamethrowers. With the day saved, the demo then drew to a close. Unfortunately, it failed to answer lingering questions about the bustling, senses-overwhelming underground towns that earned Metro 2033 so much praise – and, as a result, trading, crafting, and morality also stayed out of the spotlight.

4A Games, however, assures that those things feature just as prominently as ever in Last Light, and – in the meantime – we got to see a different kind of world-building altogether. Metro’s Moscow is coming back to life after mankind nearly wiped it off the face of the earth, but these things take time, and they sure as hell aren’t pretty. So be prepared to get very, very dirty.

Now if you’ll excuse me, I’m going to go stuff a bunch of sanitation wipes into my Official Metro-Branded Gas Mask Bag. You know, just in case.

Stay tuned to this particular frequency of the internet for an interview in the near future.