MAP21: Shaman's Device (Community Chest 4)

MAP21: Shaman's Device is the twenty-first level of Community Chest 4. It was designed by Chris Kassap (lupinx-Kassman) and uses a MIDI of "Against Nirvana" from .

Shaman's Device was featured in Doomworld's Top 100 Most Memorable Maps, placing 18th.

Essentials
Continuing off from the previous level in story, layout and theme, Kassap's other contribution is a fair challenge if you are loaded for bear after conquering, but from a pistol start, the opening sequence can be quite a rough ride. The level architecture is quite a sight to behold, but the flipside is that the open layout exposes you to fireball attacks from imps and cacodemons.

After a long opening sequence, the red and yellow keys need to be acquired in any order. The blue key is obtained right at the start of the level, and is used to operate the level's final switch.

Opening Sequence

You begin in the same darkened hallway that ended the previous level. Head forward, get the shotgun and open the door. This leads to a chamber where an imp and a Hell knight are gloating over a dead marine. Avenge your fallen comrade, then take the backpack, chaingun and blue key (don't forget it - you need it for the final switch!).

Next, head to the west side of this chamber and collect the berserk pack. As you approach the tech pillars, they will slide away, revealing an L-shaped corridor with two lost souls. Continue forward, and another set of tech pillars will slide away, revealing another L-shaped corridor with two lost souls. Head forward once more, and a third set of tech pillars will slide away, revealing the entrance to a large room with a cross-shaped walkway over purple slime.

This next room is somewhat tricky. As you enter the first half of the room, two demons will attack - easy meat for your berserk fist. Head forward and collect the rocket launcher. This causes pillars to open, revealing four cacodemons. Pull back to the entrance and lure the monsters into a bunch, then fire some rockets to take out all of them in one or two shots. As you head forward, look into the windows to the left and right of the walkway and fire a rocket into each one to take out groups of three imps bunched up there. Next, proceed west into the next half of the room with the cross-shaped walkway. This section has ten zombiemen on the north-south arm of the cross-shaped walkway, as well as eight imps on the surrounding horseshoe-shaped walkway (not present on Hey, not too rough and below). Here, a chaingun might be more effective - you need to clear out the monsters quickly and precisely while dodging fire. Once the room is clear, head to the east side of the pillars at the ends of the north-south arm of the walkway. Flip the two switches, and the long rows of tech pillars at the end will slide away, allowing you to proceed.

In the next room, watch for two Hell knights in ambush. After dealing with them, grab the box of shells and peak through the doorways into the next area first. You do not want to rush into the next area, as there are two chaingunners waiting in ambush positions. Instead, pull out the revenants, if any (none on Hey, not too rough and below; two on Hurt me plenty; three on Ultra-Violence and above). On Ultra-Violence and above, you also need to take out the two chaingunners on the pillars you can see. Once this is done, head through either doorway and finish off the two chaingunners on the pillars waiting in ambush.

Before proceeding, you might wish to clear out the monsters you see in the south - six imps on a walkway, four imps on a far set of blocks and two cacodemons approaching from the south. Once ready, head around the console and jump to the silver-bordered octagonal platform. Each platform has cover and some armor and health bonuses, but don't stay on any of them for too long - they are equipped with crushing ceilings. Follow the walkway and jump east into the opening.

This next area has two small purple slime pools and quite the complement of monsters - three mancubi on the floor, four Hell knights on a staircase-like series of ledges, and six imps and a baron of Hell on the uppermost ledge, all present on all difficulties. As you enter, two arachnotrons will rise out of the slime pools. Rockets come in handy here - after all, this room has plenty of them. Once the monsters are cleared out, climb up to the top ledge and flip the switch on the L-shaped console in the southwest. This lowers one of the blocks in the west, allowing you to jump to the red grid structure.

As evidenced by the demons running on it, the red grid structure is solid ground, even if it doesn't look like it. Hop west onto the set of rectangular blocks. Five lost souls will approach from the west - take them out from here where the demons pose no threat. Once they are dead, pull out your rocket launcher and clean the red grid structure. If you're counting your kills, there are 14 of them. Once the area is clear, hop onto the red grid structure, proceed east and jump through the opening.

Once you jump through the opening, you will be in a room with an arrow composed of armor bonuses. Watch for two chaingunners in ambush in this room. The arrow points to a pillar with a recess - grab the super shotgun from it. Next, flip the switch in the east of this room to lower the platform ahead. Don't get on the platform yet - instead, pull the two Hell knights and baron of Hell out so that you challenge them in an area with more space. Only when they are dead do you step onto the platform.

Once you step onto the platform, it automatically begins rising. The platform has two pillars with revenants - kill them quickly. When the platform reaches the top, you will come to an area with a road-like path. Kill the three imps on the ledge in the north, as well as four cacodemons which may approach from the north. As you step off the platform, prepare for a massive teleport ambush - eight imps will teleport in from each end of the "road", attempting to box you in. Use rockets while the pack is further away and a chaingun when the pack is closer. From there, head south along the walkway and head into the red and blue portal.

You will be teleported to an isolated platform with a vaguely octagonal pit. As you step forward, the floor of the pit rises, revealing three revenants and some barrels. Blow up the barrels and the revenants are toast. Head west and step into another red and blue portal, which takes you to a walkway north of the previous area. Head forward and engage the two Hell knights nearby, but be careful - when you step onto the sunken floor that they were originally on, that piece of floor sinks to the level of a lower ledge with two mancubi. Follow the lower ledge to the end, where you will find an opening overlooking the previous area with the "road". A narrow ledge will have appeared - use this to cross over to the other side.

Once you have crossed over, head into an O-shaped area with purple lights. Behind the central structure is the level's first arch-vile - not a big problem here either. Go through the door in the north to enter a dark corridor with red and blue lights, as well as crushers and seven Hell knights - still not an issue with enough rocket ammunition, or the skill to lure monsters into crushers. Follow the corridor east to its end.

Yellow Key

You now arrive at a ledge in the west of a massive open area. Your first opposition here are five zombiemen and two shotgun guys. The path ahead is blocked by red and yellow bars, so you'll have to go hunting for these keys - and each one is quite the trip.

First, head north along the ledge. This leads you to the northern side of the massive open area. Clear out all 14 imps here, then head north into a chamber mostly filled with purple slime. Kill the six shotgun guys here, as well as the mancubus on the center platform. If you are short on rockets, don't use them here - there is a spot where they will be required even more pressingly soon. Jump onto the red grid structures and make your way to the north side. As you pass through the doorway, you will find a red grid elevator platform in a massive shaft. Now do you use your rockets to kill the four revenants on the platforms before you step onto it. As you step onto it, the platform automatically lowers - fortunately, no "lowering elevator fight" here.

Once the elevator has fully lowered, head north into a room with pillars creating green sparks. This next room is fairly simple - follow the walkway all the way around counter-clockwise, watching for imps on the path, an arachnotron in each of the three octagonal structures and three mancubi on the Y-shaped walkway in the middle. At the end of the path is a Plutonia-style teleporter - step into it.

You will emerge on a circular platform in another massive lift-shaft. Surrounding you are four platforms, one in each cardinal direction, that slowly raise and lower. While waiting for the yellow keycard on a tall pillar to lower, you have to dodge fire from three cacodemons and a cyberdemon who teleports around the smaller platforms. This seems tough, but due to the design of the level, there are two "rules" the cyberdemon follows:


 * The cyberdemon can only teleport when the platform it is on is at its lowest point.
 * Every time the cyberdemon teleports, it teleports to the platform clockwise of it.

Thus, the solution to this area is simply to eliminate the cacodemons, put the central pillar between you and the cyberdemon, and move to the next position 90 degrees clockwise every time the platform the cyberdemon is on lowers completely, resulting in the cyberdemon teleporting. Unless you want to be 100% certain that you pick up the kill, you don't even need to do any shooting - once the yellow key pillar has completely lowered, just collect it and keep walking forward to be teleported between all four surrounding platforms, eventually telefragging the cyberdemon (which usually works).

Eventually, you will be teleported back to the northern side of the massive open area. Clear out the newly appeared set of three arachnotrons and head back to the western ledge.

Red Key

From the western ledge, head south and clear out the two mancubi and two barons of Hell on the steps. Follow the ledge around to a doorway to an L-shaped room. As you pass through the room, a wall in the west will lower, with two zombiemen and a Hell knight (shotgun guy on Hey, not too rough and below). take them out and continue down the steps.

This next area consists of a path over a spiked floor. Despite appearances, Kassap has been merciful - falling onto the spikes merely means you take 10 damage and are teleported back to the beginning of this stretch (instead of instant death by telefragging a voodoo doll). Over here, you have three revenants, three Hell knights and two arachnotrons to deal with. Follow the path around counter-clockwise to a switch in the northwest, which you flip to lower a block in the east.

Head to the east side of the area with the spikes and jump to the crescent-shaped series of floating octagonal platforms. Follow the platforms around clockwise. Kill the imps on the platform and watch for an arachnotron which will eventually appear in the large pillar to the south. This will lead you to a network of ledges on the east side of the massive open area.

As you step onto the ledges, they will populate with enemies from fake floor traps: three shotgun guys, two imps and one chaingunner right in front of you. Kill them, then head onto the red grid structure. At the junction, head south to get onto a broad crescent-shaped ledge. Watch for the imps attacking from the raised section of the ledge. Follow the ledge around to the north and head up onto the steps to reach the raised area. From there, go west, then north into a curved corridor with yellow and black stripes. As you enter it, the floor in three recesses in the wall will rise up, each with a revenant. Follow the corridor to its end to find a chamber with a switch in the north wall. Flip it and a nearby section of wall will lower, revealing a niche that is a teleporter. Step into it.

You are teleported to a raised octagonal platform in the southwest of this section. Flip the switch ahead of you (this releases three cacodemons from the east), then drop down from the north side on to the ledge. Continue north to another octagonal pillar and ride up the platform on its east side. From this raised area, you can jump to another set of red grid platforms. The big pillars have crushers, so be careful. At the fork,. go right (north) and make your way to the octagonal floating platform with the teleporter in it. Step onto the teleporter to be teleported to another raised octagonal platform in the southeast of this section. Flip the switch ahead of you (this releases another three cacodemons from the east).

Backtrack to the broad crescent-shaped ledge in the east and head up the steps in the north, but this time head east at the top. At the end of the raised area, you will find an S-shaped red grid walkway to a new area. This extremely tall room has a loop of red grid platforms leading to a guard tower in the east side. Collect the health and ammo on the platforms and eliminate the eight imps on the pillars in this area - you do not want them annoying you later. When you head to the guard tower, kill the two Hell knights and two revenants waiting there. Climb up to the guard tower, but don't enter it - instead, peek through the southern windows. You can pull another arch-vile out of its ambush position and slowly whittle it down through the windows. Once it is dead, only then do you enter the guard tower, flip the switch inside and collect the red key from its alcove in the north.

As you head out, you will find that two cyberdemons have teleported to the ledge in the west of this area. Due to the design of the area, they are not going to clamber onto the red grid platforms to chase you down. You just need to head behind the guard tower, dodge rockets and return fire. However, while doing this, be careful - the posts of the fence around the guard tower platform are solid, and cyberdemon rockets can detonate on them, causing damage to you!

Once all this is done, you need to make the long backtrack to the west side of the massive open area, where the red and yellow bars are.

Ending

With your red and yellow keys, you can now proceed. Flip the red and yellow control panels to reveal switches in the nearby metal pillars, then flip these switches to lower the bars ahead. Continue forward to a circular area with a spiral of metal poles. Collect the BFG9000 in the middle, then carefully climb the poles to reach the megasphere at the top. After this is done, step into the cage made of light in the east - as you might remember from the previous level, this is a teleporter.

This teleports you to one end of a hall with a tall red grid force field at the end. There is a nasty crossfire here and how to proceed is not obvious. At this point, you should save your plasma for later. First, kill the three mancubi ahead. Next, kill the six zombiemen and three cacodemons in the area to the south. Next, use rockets to eliminate the eight imps in the four alcoves on the north wall. To progress the area, step from the bright floor to the dark floor to lower a platform in the north. Step on the platform and ride it up, facing south. At the right time, shoot the red cross panel on the pillar directly ahead (think MAP30: Icon of Sin (Doom II), except with a hitscan weapon). This will lower the force-field to the north.

A spiderdemon is behind the forcefield. Give it a BFG9000 shot for a one-shot-kill - if that doesn't work, just shoot again. Head through the passageway north of where the cyberdemon was and emerge into another chamber, this time with a spiderdemon and two arachnotrons. Two BFG9000 shots will do the trick. Flip the switch in the east to lower the platform, then ride it up. As you step off the platform, the pillar in the east will open up, releasing four cacodemons - prioritise this over the baron of Hell on the ledge. Once all the monsters are dead, head to where the baron of Hell was and use the panel to lower another red grid force field to the north. Another spiderdemon lies behind it - same drill.

From where that last spiderdemon was, head through the C-shaped corridor in the west and follow it around to another group of two arachnotrons. Head north to find one more cyberdemon in a circular chamber - this one might be trickier to mow down with your BFG9000, since a cyberdemon has more health and is faster to attack. Head counter-clockwise up the steps in the perimeter of this room to a door in the west side.

Behind this door is a small red/blue crusher corridor. Open the door at its end. This leads to a large chamber with a computer panel. Finally, you get to wrap up the story and deal with the pesky "rogue AI" hinted at in the previous level. However, read the second display panel at the back carefully. That thing wants you to "entertain the arch-viles" - that's a hint to the nature of the next trap. The small raised outcrop in the middle with an invulnerability is also a hint as to what to do. Here's how to make the arch-viles entertain you instead, shortly before you end their existence with your BFG9000:


 * Flip the switch on the raised block near the console
 * Immediately back up to the raised outcrop in the middle.
 * The six chambers in the perimeter will lower, each with an arch-vile. However, this also lowers the central outcrop with the invulnerability.
 * Pick up the invulnerability.
 * Curb-stomp the arch-viles.

As the block lowers, the final switch of the level is revealed - a switch requiring the blue key. This is why it was so essential to pick up the blue key right at the start - you need it to "shut down" the system (in story) and to raise the bars trapping you in the room (in game play). Flip it, the lights go out and the bars at the entrance raise.

Head back out through the red/blue crusher corridor, and you will find that the blocking bars in the north have lowered, allowing you to access a path leading to a massive red crevasse. Just keep walking forward towards it, and after a few teleports, the level will end.

Secrets

 * 1) In the area with the two small purple slime pools past first walkway with the crushers, head down the steps to the lighter gray floor. Inspect this area for a lever switch in the northwest, then head back up to find a chainsaw in a newly-opened alcove near the entrance to that area. (sector 433)
 * 2) In the northern area with the pillars emitting green sparks, head to the octagonal structure in the west side and look south. There is a staircase heading down with four health bonuses on the railing. Step onto the railing (where the health bonuses are) and jump down to reach an area with two medikits and a megaarmor. (sector 794)
 * 3) In the L-shaped corridor just before the area with spikes on the floor, a wall opens up behind you with some monsters inside. Head to where the monsters came from. There is a blocked-off passage to the north. To reach it, head for the two steps, but be careful as there are crushers already active on these steps. Climb them and jump out of the ledge to hear a lift lowering, then quickly head through the passage to obtain a plasma gun and an energy cell pack. To exit, flip the switch on the wall southeast of the plasma gun.  (sector 1352)
 * 4) In the eastern part of the level (red key sequence), after reaching an octagonal floating platform with a teleporter, you are teleported to a raised octagonal area with the second of two switches that you need to access the final section with the red key. From this raised octagonal area, stand at the northern edge and run forward to reach a narrow ledge with a teleporter. Take the teleporter and you will be able to access an isolated cluster of floating platforms in the northwest with energy cells, a soul sphere, and a megaarmor. To exit, step off the floating platforms to be teleported back. (sector 718)

Bugs
A medikit (Thing 1327) in the south has no flags set for any of the three difficulty classes, so it does not actually appear in the level.

Current records
The records for this map at the Doomed Speed Demos Archive are:

Miscellaneous demos
''This information was last verified in its entirety on January 23, 2018.

Deathmatch
This level contains its own, separate deathmatch arena based on Kassap's Kass duel tower from 32in24 III: DUEL CORE. The most notable changes are that the exit portal has been replaced with a simple switch; the exit sign is moved from the floor to the ceiling and has had its triggers removed, meaning it does not block the exit-opening trigger anymore; and the trigger to open the exit is no longer untagged. The last two of these changes allow the level to be exited outside of ZDoom. Two start locations that originally spawned players without a shotgun unlike the others are now given shotguns for better balance. This version also removes several unnecessary sectors that were left over from raising sectors to the ceiling to create zero-height sectors rather than deleting them. It is otherwise identical to the original map.

Player spawns
This arena contains six spawn points:
 * 1) facing south-east. (thing 1504)
 * 2) facing north-east. (thing 1505)
 * 3) facing south-west. (thing 1506)
 * 4) facing north-west. (thing 1507)
 * 5) facing north. (thing 1510)
 * 6) facing south. (thing 1511)

Things
The following things (per skill level) are placed in the arena:

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

Technical information
Sliding Gates

Near the start of the level, gates made of pillars slide away when approached, stopping perfectly in alcoves made to store them. This is accomplished using a combination of a dummy sector and Boom action 248.

The gate itself is made of tall techno pillar things. The sector the pillars are on is tagged to a line in a control sector with Boom action 248: "Scroll floor and move things when sector height changes". That control sector is placed next to another control sector at a target height. A walkover line triggers the first control sector to lower to the second control sector's height. Hence, due to the line with action 248, the sector with the pillars scrolls while the control sector lowers, creating the effect of a sliding gate that quickly stops.

Floating See-through Platforms

At several parts of this map, floating see-through platforms, with their edges marked by red lines of light, can be seen. Some can even stepped on.

These sectors are created conventionally and have their floors raised to the required height. All sidedefs of the sector are given specialised middle textures, which are transparent images of the lines of light. The middle texture is offset so that its top edge aligns exactly with the floor of the sector. Next, the sector is subject to a "create fake ceiling and floor" action (Boom action 242), with the control sector's ceiling height and floor height exactly the same as the surrounding area. Thus, while the "actual" floor height remains exactly the same, action 242 draws a fake ceiling and floor similar to that of the surrounding area, causing the lower texture of the sector not to be drawn. The sector thus blends in with the surrounding area. All that is left are the middle textures, creating a floating see-through platform that can be stepped on.

For some of these floating objects that never need to be stepped on at all, all that has been done is to place linedefs where the lines of light need to be, give both sidedefs the specialised middle texture, and offset the texture to the appropriate point in midair.

The outline of some of these platforms is much brighter than the surroundings. This is done giving the platforms and a surrounding sector light levels of 255. However, the ceiling and floor of the platforms and the surrounding sector are set to the light level of the surrounding area by use of Boom actions 261 and 213 respectively. Hence, the only surfaces affected by the light level of 255 are the middle textures representing the outline of the platforms.

Of note is that this method works only where the floating platform never needs to be both stepped on and crossed under (while the visual element of the platform stays still). To do both requires the use of a self-referencing sector to create an invisible platform that raises when the player proceeds to cross it, and lowers when the player needs to cross under it.

Green Sparks in Northern Area

In the northern area, green sparks can be seen in the gaps of some pillars. This uses a particularly clever implementation of teleporters.

Every gap where the a spark needs to be present is a tiny sector with a teleport landing; all the sector's linedefs are teleport lines to the next gap in the sequence. However, each sector is also an extremely high-speed scrolling floor. A candle is placed on one of the gaps; it will begin moving and teleport to the next pillar, and so on. Due to the extreme speed of the scrolling floors, this happens so fast that all that is seen is the green teleport fog left behind with each teleport, creating the effect of sparks between all of the gaps in these pillars.

Trivia

 * After the map got onto the Top 100 Most Memorable Maps list, Chris Kassap wrote a forum post which reveals the backstory behind MAP20-MAP21, as well as a few development trivia.