Do critical head shots kill the Plaga, or just the host?
Some headbursters are RNG and some are scripted to appear in areas. I've had specific encounters from reloads produce headbursters, and then not.
How does it grade you, just time?
You need to be sub 5:30 with no bonus weapons and 15 saves. It's loaded with RNG. But, a lot of it is based on execution. Incredibly frustrating most of the time. Like there's no downtime and not being frazzled.
Killing key enemies in an area and just trying to run through it all. The current records are like two, two and a half hours and I was using old strats for it. Clearly the hardest game of the series to S rank. I had used my last save right before Krauser's main fight and I had to take that to the end of the game. Krauser is piss easy once you get skilled at knife fighting. My advice is to be super aggressive and just run in and stab him as much as you can the first round. Although if you're accurate, you can skip that first part with three well placed magnum shots, but him resorting to coming at you isn't hard. The second round you want to alternate between that, and blasting him with the magnum. I used the RPG in the third round.
I wouldn't bother with the TMP in the run. Just use Sentinel Nine, Riot Gun, Stingray and the Broken Butterfly. Use skips when you can to save yourself some headache. Del Lago was a pain in the fucking balls. I had beat him clean, with no hits. And then I died and clicked continue instead of going back to the title screen. It stupidly keeps your playtime from when you die if you just reload from the death screen. I had to fight him again and I think he killed me ten to twelve times until I understood his scripted pattern. You'll eventually be throwing harpoons before he jumps out of the water just from the areas he's pulling you to.
El Gigante was tricky, but one of the lesser bosses that wasn't a pain.
Bella Sisters were a bit tricky. Only because of the amount of enemies in that section. What was harder was the section right before that with the Brute, beartraps and the two throwing molotovs. Ashley's AI made me want to break my controller so many times. I had maybe twenty to thirty restarts right there. I saved right before it and I had to go all the way to Castle on that, so I had to do that, Bella Sisters and then Mendez on one save.
Mendez wasn't bad at all. His second form is piss easy from the second floor. Although I took some continues since I didn't shoot the barrels fast enough.
Salazar was a nightmare. First of all the elevator climb was a pain in the fucking balls since I had like nothing to fight back with. Salazar, I had one golden egg and stupidly sold the other one to get spinels. So I used one, and then I had to fight him legit with no heals and one magnum round. So I had to grab the barrels and boxes supplies there and I pretty much only used the handgun.
I used the wall clipping thing with the rifle scope at the elevator door with Verdugo so he couldn't hurt me and waited out the time. I used an RPG to blow up the dynamite wall. The core thing that saved my run was the wrecking ball gate glitch that saves like 15-20 minutes and that bypasses all that sewer bullshit with Ashley.
I used the trick to get past the minigun laser before the sanctuary so an enemy hits me through it and takes all the shots. I did it in one go somehow.
I spent the third act of Castle and almost the entirety of Island with next to no supplies, I mean literally less than 20 handgun rounds and maybe 3 shotgun shells. The Mike section was the hardest thing about the ending since the RNG elements, specifically the second part with the switches. MAKE FLASH GRENADES LIKE CRAZY. Do everything you can to have four to six of them at that part since you'll hit the second switch and possibly, the turret guy will be shooting at you as you're trying to jump the railing and knocking you back in.
I mentioned Krauser above, and Saddler I used an RPG on. Shoot him immediately with it, and when he jumps down his cutscene will trigger and then it jumps to the tentacle thing he turns into. Some advice I found out. He does have HP there, but don't shoot until Leon stops talking. He doesn't take damage during that for some reason. I had sold some weapons to fight him and I only had the Killer 7 and the Stingray.
Right now I'm doing another run on pro and cleaning up some challenges and buying all the models. I haven't tried Mercs yet but I will later tonight.
But yeah it's doable, but use current strats and not the very first ones that have gone up since almost all of it is obsolete now. The first runs were like 4:30 on average and Bawkbasoup went from that to like 2:30 in a week.
