su18-5601_txt_part2

Route/Strategy:
I rush for the first revenant as I don't want to dodge the second revenant's missiles.

One can run around the linedef at the switch and open up the bars blocking the path forward. Then you can immediately kill the cyberdemon so he's no longer a problem and also kill the arch-vile before starting the fight. Usually there's just enough ammo that infighting isn't that important, but I might leave the hell knights and barons alive for a while to see if the cyberdemons get to them eventually.

Now there are 3 directions you can choose from, one for each key. Yellow key is by far the easiest, there is hardly any chance of dying unless some major mistake is made, which means yellow key is done last. Red key is shorter than blue key, but the first 2 parts of it are trivial, the final part can be a problem, but there's probably a 75% survival rate here, but I'm not certain. So I like to look at blue key as 3 separate shorter fights that can kill you and red key as 1 long fight, hence it's better to go for blue key first.

Blue key:
Just going to cheese the first fight and stay by the first switch until the fight is basically over. Just need to take care of the closest revenants by the arch-viles which can be done without having to drop down. The rest is just running close to the edge to get infighting going and use some rocket splash. It's possible you just take too many revenant rockets at the start though so it's not that easy. After a while I jump down on the right side corner since there's a bit of room there. Cyberdemons usually have a lot of health left so it's best to plasma them down once all the arch-viles on the ground are dead.

Next part I just activate both switches and leave, doesn't really matter much what I do as I'll just grab the megasphere at the start of the next fight. I can't really grab that megasphere while the fight is going and I have no need for it afterwards.

So second area I am supposed to wake up all the cyberdemons first, then activate the switch followed up by just jumping over to the arch-viles. Lots of pain elementals will come around the corner and they need to be dealt with as soon as possible. However you are safe from everything else as long as you pay attention so this strategy is pretty good. I think I used it in my first playthrough and it has just worked every time. Once you run out of rockets you might have to go grab some more, can also pick up the mega armor and the soulsphere safely. Cleanup is trivial afterwards.

Last area it's all about surviving the invulnerability run to the arch-viles. I tried a bunch of different stuff so that I didn't have to rely on good luck, but nothing really seemed to be better. Once that's over the fight is done assuming you don't take some unlucky rocket somehow or just have really really bad luck with baron/hell knight movement. Just got to run out on the left side which is usually clear or blocked by pinkies at worst, then you can circle around by running up the small stairs that lead up to the invulnerabiltiy. Sometimes I have to run into the stairs leading up to the cyberdemons in order to get them to teleport.

Red key:
The initial fight is all about avoiding getting thrown off by the arch-vile, there's a soulsphere and you're probably maxed out from the previous area so just don't fall down.

Now I found an easy way to do the very first hive mother fight, which is to just use rocket splash. Then the one on the left can't see you while the one on the right and the center can't actually reach you, so we're done here.

Spiral area is easy and then there's the part where you just hope you don't get unlucky with bad monster movement. Need to run past the arch-vile so I don't wake up all the monsters unintentonally. I kill a few of the hive mothers first since the remaining ones will easily win against the cyberdemons, making this fight much less risky. Then I run to the back behind the pillar and wait for a good opportunity to run past for the second switch. Dodging the cyberdemons is usually easy as they frequently infight. Then just use rockets from the other room.

Last fight can be dangerous if you get unfortunate hive mother movement. I'll start with clearing out as many hell knights as I can before the hive mothers get too close, just need to get rid of them and the cacodemons and the fight should be over. After firing the initial rockets I go to the side area and run around to the other side, I'll turn around if there's a hive mother waiting for me and just go back the other side until one of them allows me to run by. I'll either circle around or run back depending on how the monsters are positioned. Just keep doing this until most of the cacodemons are dead to infighting and then the rest can be killed from the side area.

From the side area I'll stand close to one of the walls where as far as I know they can't hit me, so I'll quickly poke out and hit them with the SSG. If they get stunned then they'll fire 3 rockets dealing splash damage, so the SSG is quite effective as the rockets will hit the floor. However there's a chance of elastic collisions if you're careless, I think it should be consistent if done right, but I'm not completely sure. It worked often enough in practice that I don't see it as an issue if it does fail sometimes, as I doubt there is anything that's less of a risk and faster. Once ammo is out there aren't that many left alive so it's easy enough to kill them with rockets or plasma. Movement is a bit difficult because of the floor and elastic collisions, so it's best to be extra careful.

Yellow key:
Get all the cyberdemons to the upper corner to infight the hell knights/barons. I'll just sit by the first switch until it's safe to leave. So obviously the arachnotrons are killed first, nothing can really hit you from the opposite side of the stairs, so you just need to focus on the cacodemons and pain elementals trying to move up. Next to the stairs there will probably be revenants which prevents cacodemons from getting to you as well. 2 Arch-viles come from the entrance/stairs direction and 1 from the side, so they can most likely be killed with splash damage off the tower or off the cacodemons. Remaining rockets can be used on the tower behind you for good splash damage on the hell knights/barons. Sometimes I run close to the edge to get cyberdemons to start infight, had a few of them hit me in practice so it's important to be quick about it. The megasphere also has a box blocking monsters between it and the platform you're standing on, so you can easily grab it without having to worry about infinite height.

Next section is straightforward, just run with plasma rifle, there's 1 part with 2 revenants around a corner so I'm a bit careful there to not end up between them and having them both attack at the same time. Use rockets to kill the arch-viles from the last room, there's a megasphere if you need it and so much health coming up so just need to survive.

2 more fights to go and one of the switches can be activated through the wall leaving you with a choice of which to begin with. Since there's a megasphere + ammo in a room that gets closed off once you start the first fight I'll go with the 2nd fight first.

Again we'll release the cyberdemons first, then I'll use one of the corner elevators to run along the edge so that I can avoid closing the room off. If I cross the linedef leading up to the throne then I can't go back. Need to wait a bit at the throne to get the cyberdemons a bit closer towards you. Immediately afterwards I'll go for the next switch which releases 4 arch-viles and another cyberdemon, need to be really quick with the switch so the cyberdemons don't land a rocket. Waiting for a moment behind the wall incase the cyberdemons are already firing might also help.

Then run outside, fire rockets into the room and avoid hitting the cyberdemons so they don't go chasing you down and just don't get hit by cyberdemon rockets. The courtyard fight is identical, just release the 3 cyberdemons and run into the back corner. From there I just need to get to the switch and get past the monsters teleporting in.

It's possible to run through to blue key and return to it later, the same can also be done for both the other keys, but would require some difficult linedef skips that don't look too viable without TAS. No idea how much time this would save, but probably quite a bit.