MAP20: Beneath the Waves of Styx (Sunder)


Sunder maps 11-20

01 02 03 04 05 06 07 08 09 10
(11 - 20)
Secret maps: 31 32

This level occupies the map slot MAP20. For other maps which occupy this slot, see Category:MAP20.

MAP20: Beneath the Waves of Styx is the twentieth map of Sunder. It was designed by Insane_Gazebo and uses the music track "".


Map of Beneath the Waves of Styx
Letters in italics refer to marked spots on the map. Sector, thing, and linedef numbers in boldface are secrets which count toward the end-of-level tally.


When the lift descends, leave and explore this area, finding boxes of shotgun shells near a pillar that has both a super shotgun and a shotgun, a megasphere and more boxes of shotgun shells to the north, a stimpack to the east, several more boxes of shotgun shells and stimpacks at the peripheries, and an ammo clip by a switch. There is also a rocket launcher to the south, as well as a switch and a lift, however you cannot use them yet. To start the first fight, you must shoot the switch, but get ready when you do. In fact, it is preferable if you stand close to the pillar with the shotguns, as when you shoot the switch, not only does that pillar lower, but also a bunch of blocks will lower. Hell knights and barons of Hell will teleport from the west, and two cyberdemons are being released closest to the switch. Four arch-viles are in cages to the south near the rocket launcher pillar, and chaingunners are on blocks outside the fences. Lost souls will also teleport in from where the cyberdemons are. As you fend them off, you may notice a new skull switch near the rocket launcher. This lowers the rocket launcher, but also opens the south alcove with more arch-viles as well as rockets inside. This alcove contains another switch. Using it will raise the lift you could not use before. Now that it is all the way up, take the lift up, and use the switch to the east. This allows you to trek east out of the first area.

In the next area, if you need a megasphere, one is to the northeast. The switch at the southeast end will let you take a lift up to eight health bonuses, and there are stimpacks and boxes of shotgun shells lying around the room.. There is a square of sixteen rockets in the middle but you cannot reach it yet. The switch you need to press is at the north end. This releases a cyberdemon to your right with a stimpack, an arch-vile in a cage at the east end, two nearby compartments with nine revenants each, another one with nine revenants to the south, and the upper walkway in the center has five arch-viles. The square with the rockets will also lower when you use the switch. As you deal with the enemies, the next switch is in the north revenant closet, then the next switch after that is at the upper walkway in the southeast past (with the health bonuses, in a room with boxes of rockets). That switch will raise bars to the area with arch-viles, which has the last switch, allowing you to exit north. Follow the steps down to the next big area.

A megasphere is in front of you, and you can get a chaingun and ammo if you head around the central structure here. There is also a lift to the south, but you cannot use it yet. A backpack is in the center, along with the switch you need to use. This locks you in and reveals another switch to the east. This switch is one you need to shoot, and doing so will cause imps to teleport into the square you are in, while cacodemons attempt to enter the square from outside. Eventually, a lift rises from the north. Take it to leave the square, and this will also raise the lift you could not use before. Take it up. A megasphere, boxes of rockets, and boxes of shotgun shells will be here as needed, and when you are ready you should press the switch at the north end. This will release a cyberdemon to the east, with an arch-vile in a cage to the north, as well as the outer wall to the south, which has Hell knights, cacodemons, imps, and arch-viles (four are in a cage at the next switch, and one is in another cage south of it). There are medikits and boxes of rockets as needed, but you should press the switch near the big cage when ready. This will lower a wall near the previous switch, and from here you can jump two pillars, then into the hole on the west side to continue north. The switch in the hole will lower the wall in case you need to backtrack.

The next room you come to has boxes of rockets, boxes of shotgun shells, a megasphere, and medikits lying around. You will also see the plasma gun, an energy cell pack, and energy cells on a pillar. The switch at the south end releases demons at first, but you need to prepare for the second wave, as the walls at the north and east ends will lower, revealing imps, arachnotrons, as well as three arch-viles coming in from the southeast. The plasma gun will have lowered at this time, so now you should take it. Climb the outer ledges to the switch at the end, which opens the way westward so you can go back outside.

Take the lift down and you have an extremely large area to tangle with. Supplies are dotted around as usual, and a yellow key switch is near a gate north of the lift. There is a nearby cemetery that is also locked. There are a number of ways to get to the central structure, but you should be wary of the slime surrounding it, as well as several holes of black sludge you cannot leave if you fall into. The central part of this structure has an entrance at the west side, but it is locked. At the west end is some steps leading to a red key switch, and if you head south from there you can find steps leading to another area, but it is locked. Another area to the northwest is locked, and you may also notice a boat with a megasphere on it. There is no way out if you fall there, though, so leave the megasphere for now. The area to go to is southwest of the dock, down some steps and across platforms to a sewer system. It empties out in an area with a megasphere and several dead bodies.

Climb the steps here and use the switch, which releases four barons of Hell to the north as well as demons and revenants to the south. The switch where the revenants were lowers bars to the east, where you can pick up a soul sphere among other goodies. The next switch here must be shot, which releases a cyberdemon to the north. The outer wall of Hell knights will be lowered, while imps teleport from the west square. The next switch where the cyberdemon is will raise steps to the ledge with Hell knights, where you can get a green armor and another switch. You can now exit this area to the northeast. Open the door and use the switch in the next hall, which reveals another outer hallway full of imps. Chaingunners will teleport from behind the fence, so use that outer hallway for protection. When done, the next switch is at the north end of the hall with imps, allowing you to move westward.

Take the long lift up, scouting the next area for a megasphere and ammo. Make sure not to fall as you go on the platforms. At the square platforms, one will eventually rise up, preventing you from backtracking, and when you continue further a block of nine revenants shows up to the southwest. Note the switch where they are, then continue across the blocks to the east end with a mancubus. Backtrack a little and you will see a chaingunner near another switch. The switch here raises some platforms that were down, as well as teleports in arch-viles where the revenants were. The new platform that raises serves as extra room for dodging, but when you are ready, go to where those enemies are and use the switch you saw before. More platforms will be moved, and cacodemons will attack from the west while a cyberdemon is to the north. Your goal is to get to the platform with the cyberdemon, using the switch there. This allows you to head back to where the mancubus was, which now has a pathway to the cacodemon cage. The switch there will unlock the cyberdemon platform, where that last switch will raise platforms to the north. Take the lift up once you get there and use one last switch to reach a teleporter.

You will be back at the central field and the central structure, with three switches in front of you. Use all of them, as they will open several locations around the central field, which you can take on in any order. First, head to the southwest end, up the steps and to an area with a megaarmor, medikits, ammo, and some pits you will want to avoid. Upon using the first switch, lost souls will teleport around the area, so keep on your toes until the switch at the east end lowers. Be wary of three arch-viles, then use the switch to leave. If you head back to the three switches from before, you will notice that the right one has disappeared. Next, go northwest, up some steps to a caged area with ammo at the peripheries and a megasphere. Use the switch at the west end and prepare to deal with revenants and arch-viles in a cage, as well as cacodemons and later pain elementals teleporting in. Use the switch at the west end of the cage now to enter it, then use the switch inside to get out. If you head back to the three switches, the left one has disappeared. Now it is time to enter the cemetery to the northeast. As usual make note of the supplies before using the northeast switch. Two cyberdemons will teleport in at the northwest end, and several crypts will lower revealing two arch-viles in each, all while revenants and imps teleport all around the cemetery. The switches at the southeast and west ends will let you leave this area.

Assuming that you have tackled all three areas northeast, northwest, and southwest of the central structure, all three switches there should have disappeared and you should now be able to enter the central structure. There is lots of ammo at the perimeter and a few health pickups dotted around. At the north wall and the south wall are three switches, and there is also a reset switch at the north wall as well. The switches at the north wall change the shape of the room to certain patterns, and you can only have one at a time, so you must reset if you wish to try a different block pattern. The switches at the south end release monsters, with the left one releasing arch-viles, revenants, and imps. The middle one releases a Hive Mother, Hell Knights, chaingunners, and arch-viles. The last one reveals arch-viles, revenants, and shotgun guys. You have to use the switches at the south end to get the red key, but you will also need the switches at the north end to help battle the enemies that spawn in. Using any of the switches at the south end reveals switches at the west end. Using all three of those switches will allow you to get the red skull key as well as leave the central structure. After getting the key, head out and go to the west side, climbing the steps where the bars are and using the switch at the top. The switch will lower the BFG9000 as well as bars to a switch west of it.

Use the switch and prepare for battle, as the central field will populate with monsters. Two spider masterminds teleport onto the big blocks north and south of the switch, while revenants will spawn in from the three large platforms, two of which are flanking the red key switch and another is at the northeast end. Hive Mothers will also show up from these areas, and cacodemons will also teleport in. The energy cell packs around the switch and BFG9000 will help, as well as another northeast of the red key switch and a megasphere southeast of it, both of which have lowered from pillars. Eventually, the slime river in the middle will also rise up, and you can get the megasphere that was on the boat earlier. Look out for cyberdemons which spawn in, though. The next place to go when you are finished is to the northwest, across some blocks with candles. Pick up a soul sphere if needed, then go until you get to a switch. This will finally lower the west wall in the central field.

The next battlefield you come to has plenty of ammo and health scattered around, along with two lifts at the north and south sides of the entrance, which are not high enough to be used yet. Two megaspheres are near the switch at the west side, which is your target. Shoot the switch and be prepared to battle against eight arch-viles coming from the north as well as lots of spectres coming from the south. Use the columns to avoid attack, but watch your back as you do. Another group of eight arch-viles will teleport from the north end as well. Soon, parts of the floor will sink and become nukage, while four Hive Mothers come in as well. When you are done, go back to the two lifts near the entrance, take them up, and use the switch up there for each one. After using both switches, the west walls to the north and south will lower.

Go to the new area behind the battlefield of columns and get ready. You will be locked in and will have to tangle with hordes of Hell knights from the north and south ends, as well as a horde of revenants from the south. The safe spaces where these enemies are have some ammo. You may also be tempted to run northwest, towards the megasphere and more items, but there is also a wall of revenants and no less than sixteen Hive Mothers to contend with here as well. A path of health bonuses is at the highest end at the northeast part, which can serve as an exit chute down if you ran from enemies and lured them further up. There are four switches to press. One is at the base of the chute and the second is where the revenant horde came from. The other two are in the leftmost compartments where the Hive Mothers came from. After using all four switches, head southeast of the Hive Mother compartments. Follow the long set of steps and you will eventually get to a switch. This opens up the bridge north of the Hive Mother compartments. Go there, pick up a megasphere is needed, and climb another long set of steps (there is a wall of health bonuses you can pick up along the way). The switch here will open up the next area to the east north and east of those steps, with green laser barriers.

There is a lift at the east side, but it is not available. Instead, take the lift at the north end up and use the switch to the west. Three cyberdemons show up along with an arch-vile on the pillar. Press the east switch to leave, then drop down and head to the area to the north. Several monsters are behind the lasers, inactive. The southeast lift leads to a megasphere. You also have a switch column at the north end. The switches have a number and a monster on them, with "1" referring to barons of Hell, "2" referring to revenants, and "3" referring to Hell knights. Pressing any of these switches locks the other ones on the pillar, as well as releases a cyberdemon to the west and arch-viles on a block north of it. Another switch to the west will be available. Use it and head on over to the east side to another switch that was blocked off by bars. This opens the way to the east side. At this area, get supplies if needed, then head to the east side to find several number bars as well as the remaining two number switches that you did not press. Whichever one of those number switches you press, you will have that type of monster teleport at the southwest and north ends, while arch-viles appear on blocks a bit west of those switches and the wall of Hell knights to the south opens up. You should have one number bar left, but before lowering it, you need to use the switch at the north end and a switch at the south end as well. These remove bars to a skull switch just below the number switches. Use that switch, and you open the two eastern halls behind the bars. Enter the south hall, take the lift up, and use the switch. Defeat four arch-viles, then you can take the lift back down when a switch appears. Enter the north hall and do the same process, this time with a Hive Mother. Back at the east side of this area, head southwest through the passage. From here, you can go east, but if you want to get the last number switch, head left, off the lift, and south. This switch will release the last batch of monsters, three arch-viles on blocks to the west, and a wall of revenants behind the lasers to the east. The switch where the revenants came from will let you leave to the north, although this may not be needed if you came from the high walkway to the east, which you should now head back to.

Head east and all the way to get the yellow skull key. Use the skull switch north of it and descend the steps, then use another switch and you are back at the central field. There is nothing new in the field, but now that you have the yellow key, you should use it at the northeast end near the cemetery. This opens the gate, allowing you to head further north. Your goal is the north door, but it cannot be opened yet. You can climb the structure to the west with several supplies, most of it being cell ammo. Use the switch on the west side of the central building here, and you will realize why all those pillars are there, as chaingunners will teleport in from all the corners. Keep on your toes, and then go to the west side to collect both a megasphere and partial invisibility which you should do while the chaingunners are teleporting in. The switch will let you leave, and you will also be able to go through the large gate at the north end. Fall into the large hole and traverse the platforms to get to the final arena.

Make note of all the ammo around and the three megaspheres (your only source of armor and health), then be prepared to fight off waves of imps that warp in, as well as cacodemons from the outside. Also watch out for the Hive Mothers who will snipe at you, and occasionally warp in as well. Look out for barrel explosions that can happen on teleporters too, as they can come without warning. After some time, the cyberdemons will join in the fray, so it is recommended to mop up quickly before this happens. You then have two switches to press, one at the southwest end and one at the east end. Use both switches, then fight the last ten arch-viles which teleport in from the north. Follow the floating torches to get to the exit.

Other points of interest[edit]


There are no official secrets on this map.


Demo files[edit]

Areas / screenshots[edit]


As this level does not contain official secrets, the NM 100S category is redundant.

Routes and tricks[edit]

Current records[edit]

The records for the map at the Doom Speed Demo Archive are:

Run Time Player Date File Notes
UV speed
NM speed
UV max
UV -fast
UV -respawn
UV Tyson
UV pacifist

The (absence of) data was last verified in its entirety on April 4, 2022.


Map data[edit]

Things 7294
Vertices 54347*
Linedefs 63639
Sidedefs 48811
Sectors 13467
* The vertex count without the effect of node building is 54347.


This level contains the following numbers of things per skill level:

Technical information[edit]

Inspiration and development[edit]

During development, this map's working title was "Jade Ossuary".[1]


See also[edit]


External links[edit]


  1. Insane_Gazebo (4 November 2021). Doomworld forums post. Doomworld forums. Retrieved 29 June 2022.