Purist first room is a challenge where you play on hardcore, you can’t open any doors and you are only allowed to use frag grenades/acid bombs and wall weapons, you are not allowed to use elixirs or special weapons and this is the world record strategy guide for it.
Important tips: Shooting the zombies in your way with your strife while training shocks them and allows you to run past them without getting hit, if you abuse this mechanic correctly getting to high rounds on this room is going to be easy for you. Here’s the world record montage showing the clips where it was used to do it . When you don’t have grenades after collecting the hoard just shoot the zombies with your strife .
Setup: Starting weapon: Welling, Acid Bomb Strife attachments: includes operator mod, extended mags and laser sight
Rounds 1-7: jump over the bus to Site Entrance and kill zombies from all windows with strife if you get pushed train zombies around the room until you have a chance to shoot or nade them.
Rounds 8-15: start at the door that is further from strife wall buy leading to saug wall buy outside the room, go to middle (between strife and bus) and try to collect some zombies by going in circles, then go to opposite side of the door you started at, shoot the zombies in front of you to avoid them, go in a circle around the whole room slowly to pack zombies together and then do a cutback in middle around strife to reverse your path and collect the full hoard then throw an acid bomb in front of them to kill them all and repeat. You can go around the whole room twice if the zombies where split apart.
Rounds 15-25+: start at the same door as rounds 8-15 but instead of collecting some zombies in middle, go around the room in a circle or 2 ( depending on zombies being split or not) straight away then do the cutback at the strife to collect the hoard and nade the same way as rounds 8+. Dogs start spawning mid round on 15 so try to avoid them while hoarding up and after you’re clear kill the dogs, wait for respawners and nade.
Rounds 25+: At this point it’s your choice to do what you decide, hoard ups are the same as rounds 15+ but the only difference is in killing the hoard, nades aren’t as efficient on these rounds meaning that after nading the hoard you will have left over zombies and crawlers that might force you to hoard up sooner than respawns get to you which makes the room a little bit more RNG based so you can either headshot the zombies and kill less at a time, wait for respawners and repeat or just keep nading till you stop nading later on in the game. You can also predamage the hoard before nading to avoid left over zombies. Personally though I would stop nading on 25 since thats how 27 game ended by nading and bad RNG with dogs.