MAP14: Downriver (Community Chest 4)

MAP14: Downriver is the fourteenth map of Community Chest 4. It was designed by Eli Cohen (ProcessingControl) and uses "Anchor," a music track composed by Mark Klem for Memento Mori II.

Essentials
Most of Downriver's action takes place along a "2"-shaped axis of hallways, which you have to traverse up and down thrice. With every pass, the corridors refill with enemies. From a pistol start, you do get a rocket launcher and a good amount of rockets. However, going trigger-happy with rockets may not always be the best idea, as splash damage is something you have to bear in mind within this map's rather tight confines.

Completion of the map requires obtaining the blue key, then the red key, followed by the yellow key.

Start and Blue Key

You begin on a raised ledge in a grey brick room. As soon as the map begins, the two large metal pillars ahead will begin lowering, revealing some strong enemies (two Hell knights on Hey, not too rough and below; one mancubus on Hurt me plenty; two mancubi on Ultra-Violence and above.) Grab the four boxes of rockets to the right, then dash forward and use the green pillar. It will slowly lower, revealing a rocket launcher. Again, quickly dash forward, grab the rocket launcher, then retreat to the ledge to blow up the enemies. Once this is done, get off the ledge and head through the door next to the left metal pillar.

In this next room ("red door room"), there are up to six imps beyond the four pillars in this room. Blow them up with your rocket launcher - no big deal. As you head past the pillars, face backwards (south). The walls in the south of the room will open, revealing up to three arachnotrons. This room has the red door in the northwest, so remember that for later. if playing from a pistol start, flip the switch in the north to lower a chainsaw, which may come in handy for close quarters situations.

Once the room is clear, head through the door in the east. This takes you to a darker hall with windows overlooking a river ("revenant hall"). As you enter the room, an invisible ledge lowers, releasing up to six revenants into the room. You also have to deal with up to six imps in a long cage to the left (north), and up to two cacodemons that will approach from the windows. Pull back into the previous room if you need space to dodge homing missiles. This hall does contain some delayed ambushes, so be careful when you have to pass through here again later.

Continue east. You will now be in a much taller hall with high ledges ("ledge hall"). Part of this hallway splits into a lower, accessible ledge and a flight of steps going down. Kill the arachnotron on the ledge directly in front of you. Next, clear out the revenants on the ledge to the southeast, as well as the horde of imps on the steps going down. You may also wish to clear out the arachnotron on the lower ledge (not present on Hey, not too rough and below), which is guarding some boxes of rockets. Once done, head down the steps. There are two mancubi waiting at the bottom near the door - you might wish to pull them out to the steps so that there is space for you to use your rocket launcher.

At the bottom of the steps, switch to a close range weapon, and open the door ahead. This leads to a square area with a spiral staircase. There are three imps on the way down - no big deal. Open the door at the bottom of the spiral staircase, which leads to a hall with blue and red inlays ("red/blue hall"). In front of you are up to six imps, but the real danger is the mancubus just left of the door as you enter. About 1/3 of the way down the hall, an invisible tripwire causes a shutter at the end of the hall to open, revealing a platform with an arachnotron. Dispose of it with more rockets.

At this point, you probably should make a detour for a chaingun. From the middle of the red/blue hall, head south. Kill the arachnotron on the platform, dash up onto its platform and grab the chaingun (and two boxes of ammo. You do need to be careful of an imp cage on the right (west) wall, as well as a thin window right (west) of the chaingun platform where an arch-vile can launch attacks at you. It is well advised to clear them all out now, as you will be visiting these areas later.

Head to the arachnotron platform at the west of the red/blue hall, and get up on it using the steps. From there, proceed south into yet another hall ("shutter hall"). This one is blocked off at the end by a lowered shutter. Grab the super shotgun here. Kill the three imps and arachnotron ahead. As you continue down the metal steps, up to three revenants appear on the ledge to the east. Get up to their ledge using the nearby steps. On the southwest of this ledge is a patch of brown wall, in front of which are lights on the floor. Open it, and you will find yourself in the imp cage overlooking the chaingun area. Head to the south of this cage and step into the alcove with the armor bonus. This alcove lowers you into a new room, where the arch-vile overlooking the chaingun area was. Head to the southwest of this room and flip the switch.

Backtrack to the shutter hall (quickly, as up to four cacodemons have been released in the chaingun area). The door in the southwest leading to a bridge is open. Head along the bridge to enter an octagonal building. Access to the central structure of this building requires the blue key, which you don't have yet. Clear the central ledge of the eight mancubi. head up onto the ledge and flip the four switches (one in each of NE, NW, SE, SW sides of the central structure), then head back to the shutter hall.

From here, go back north to the arachnotron platform west of red/blue hall. On the west wall of the arachnotron platform is a recessed brown wall. Open it, kill the imp inside and grab the blue key.

Red Key and Yellow Key

Head back to the shutter hall. A trap has opened near the steps leading up to the ledge, with three revenants. Take them out. Again, head along the bridge and into the octagonal building. Use any of the blue doors to head into the central structure of the octagonal building. It is completely quiet inside, with the red key in the middle. Any half-skilled player would have their "trap" alarms going off at full volume right now. Equip the super shotgun, jump down and grab the red key. Four nearby pillars raise, revealing four Hell knights. Weave around them and blast them at point blank range.

Ride any of the platforms in this area back up, and backtrack to the shutter hall. At this point, you might notice about five revenants (and four cacodemons) in the shutter hall heading for you. This is because collecting the red key has opened up a large number of traps in the level. As you make the trek back to the red door near the start of the level, these are the traps that you will encounter:


 * Red/blue hall: Up to eight cacodemons are released from the chaingun area. A trap has opened in the east with two mancubi (one on Hey, not too rough and below).
 * Ledge hall: As you approach the top of the steps, parts of the northern ledges lower, revealing up to eight revenants. Don't get backed up into the lower ledge - there is a fresh arachnotron waiting at its end!
 * Revenant hall: As you proceed west across the room, two traps open behind in the east, with up to four revenants in total.
 * Red door room: A trap with a mancubus (two on Ultra-Violence and above) opens in the northwest.

Open the red door. This leads to an elongated octagonal building. Head around it, watching for a Hell knight on either side and two imps at the back. Enter the center of this structure and kill the arachnotron and two imps inside. The yellow key sits atop a pillar. As you walk up the pillar, steps rise up to the surrounding ledge. head onto the surrounding ledge and jump to the yellow key. At this point, up to ten imps will appear on the surrounding ledges - get out of the central structure and use your chaingun to mow them down.

Exit

You now need to retrace your steps all the way to the shutter hall. Again, grabbing the yellow key opened a new host of traps. In order:


 * Red door room: The trap with a mancubus "refreshes" - a wall in it opens, revealing two mancubi (one on Hey, not too rough and below).
 * Revenant hall: As you proceed east across the room, two traps open behind in the west, with up to four revenants in total.
 * Ledge hall: A new arachnotron and new revenants appear on the upper ledges. Up to three revenants are released onto the lower ledge. A new trap opens at the base of the steps, with an arch-vile (not on Hey, not too rough and below) and two mancubi (Ultra-Violence and above).
 * Red/blue hall: A wall in the southwest lowers, releasing up to three revenants. On Ultra-Violence and above, the arachnotron platform at the end has an arch-vile on it.

The shutter at the end of the shutter hall is now open. Up to three revenants will approach. Grab the armor if needed and head down the hallway. Step on the square with the armor bonus to be lowered into the exit corridor. Watch for the three imps high on a ledge to the right, and a mancubus dead ahead (Ultra-Violence and above only). Open the exit door, prepare your rocket launcher and step onto the bridge leading to the exit switch.

About one third of the way along the bridge, the sides of the bridge suddenly sink into the lava. Alcoves open on either side of the bridge, revealing up to ten Hell knights. If you want to get out of this one unscathed, you'll need to unleash skills normally meant for another genre of video game - bullet hell. Try to clear out one alcove as soon as possible, before dealing with the other alcove.

After a while, the ends of the bridge will rise up again. Flip the switch at the end of the bridge to exit the map.

Official

 * 1) In the second room you come to, flip the switch to lower a lift to a chainsaw. Ride it up, and look east to find a switch. Shoot it and then flip the other switch to lower yourself back down. One of the columns here has lowered so you can get a backpack. (sector 875)
 * 2) In the same room, if you approach the imps, a wall with arachnotrons is revealed behind you. Look at the green walls here and notice that one of the walls has gray lights instead of blue lights. Press it to reveal a corridor. (sector 52)
 * 3) In the hall where an invisible ledge with revenants is lowered, ride up the small platform in the northeast of the hall, set into the raised north side of the room. Go through the door on the left, outside, and then inside the small corridor. When you reach the door, open the wall to the left of the door for a passage going back. (sector 3105)
 * 4) Open the wall to the right of that same door for a teleporter. (sector 3109)
 * 5) Take this teleporter, but do not step off of it. Instead, open the wall behind you for a megaarmor. (sector 1083)
 * 6) At the eastern hall, take the stairs south and open the next door. Look to the right for an X on the wall. Shoot it, then descend the stairs and you will find an opening in the north side of the central pillar. Get onto the ledge surrounding the central pillar and move to the opening before it closes to get a megasphere and two boxes of rockets. (sector 2561)
 * 7) South of the hall with red and blue insets in the floor is a large room where you can collect a plasma gun and a chaingun. Go around and behind the chaingun's platform and head directly behind it to be lowered to a box of shotgun shells. (sector 238)
 * 8) To get this secret, head onto the chaingun's platform to hear a door opening. Go back to Secret #7 to find another opening where you can get another soul sphere. (sector 1227)
 * 9) On the bridge leading to the building surrounded by water, if you look to the southwest, you will see a small dark patch of wall to the right of the furthest pair of gas lights. A switch is behind this wall. Shoot it, head to the red key building and go around to the other side to get two boxes of shotgun shells. (sector 3404)
 * 10) When you grab the blue key, you also open up a closet with revenants inside; this closet is at the top of the stairs in the hallway that is south of the blue key. Enter this closet and use the brown-wired wall to lower it for a passage (sector 1580) containing six stimpacks, ammo boxes and a way to the imp cage overlooking the chaingun room.
 * 11) After grabbing the red key, several traps open in the previous areas. As you backtrack to the red door, you will find a trap in the southeast of the hall with red and blue insets in the floor with mancubi in it. Inside this niche, press on the second vertical set of gray plates to the right of the computer terminal (it's entirely unmarked) to open a passage (sector 610) to a room of revenants, boxes of rockets, and ammo boxes. Inside this room, if you press the switch, a window appears in the south of the room. Press it again to reveal a conveyor belt with bodies and an armor. Press the switch one more time to "deliver" the armor to an alcove in the east of the room, where you can pick it up.
 * 12) In the yellow keycard room, press on the wall that says UAC to lower it, then ride it as a lift. At the top, shoot the skull switch to reveal another switch in the room. Flip this switch, which lowers the western windowsill so you can drop into the pool. The railing on the western part of this area has also lowered, step on it and rise up to get a medikit and some supplies. (sector 547)
 * 13) This secret is best collected together with secret #12. Flip the hidden switch in the yellow key room that lowers the western windowsill and railing to get to Secret #12. Drop into the water, then press the unlowered half of the windowsill from the water (it will lower). Head onto the railing to get to Secret #12, then run all the way east and you should get a megaarmor before it rises. (sector 652)
 * 14) Near Secret #13, in the same general area accessible from Secret #12, there is a portion of the rocky wall that is misaligned (it can also be spotted on the automap as the only part of the northern wall running perfectly east-west). Press on it to lower it, claiming a berserk pack. (sector 3342)
 * 15) Once you grab the yellow key, leave the area and come back to some mancubi attacking you. The gray-walled closet that they were in has a metal wall. Press on it, then run into Secret #2. An alcove near the entrance to the secret will have temporarily lowered, with a soul sphere. (sector 973)
 * 16) After getting the yellow key, head back to the hall where the invisible ledge of revenants was (this area probably has more revenants in it by now) and take the lift up again. Follow it to where Secrets #3 and #4 would be and, if you have not already done so, open the door and flip the leftmost switch. This opens up a corridor just before the door. Take this corridor, up a lift and onto a gray ledge with lights, going around the gap to the other gray ledge with lights. Now drop onto the gray ledge that does not have lights and head into the green-floored area. Another room will open and revenants will be lowered from columns. If you look to your left in that area, you will spot an opening you cannot reach as well as an indentation on the right wall. Press this indentation to lower the wall behind you. Now, in order to access the opening, you will have to retrace your steps a bit. The quickest way to do so is to drop into the big hallway nearby and lower the wall in the revenant closet (this closet opens when you are heading for the yellow key after picking up the red key). There will be an arachnotron when you lower the wall, but you want to ride it back up. After doing so, go back to the wall you lowered via the indentation on the wall, and you should access the opening. Head inside and flip the switch to raise the columns the two revenants were on. Now use one of them to rise up and then hop into the corridor with health and armor bonuses. (sector 668)
 * 17) Open the yellow door near the exit of the level. When you approach the middle of the bridge with the rocket boxes and stimpacks, the ends will lower and you will be stuck in the middle against several Hell knights for a while. When the ends of the bridge rise back up, you can head to the exit, but before you do so, head back through the door you came in from. There will be a new opening on the left side, leading into the teleporter that was accessible from Secret #4. Go through this teleporter, and there will be another open passage in front of you, leading back to the two switches and the imp cage. Flip the rightmost switch, then quickly run back through the teleporter heading close to the yellow door. A ledge with armor bonuses and imps has lowered, and there is an opening you see leading outside. Wait for the ledge to rise and jump through the opening and follow this path to energy cells and a berserk pack. (sector 1369)
 * 18) Near the pickups available from Secret #17, there is an indentation on the wall. Press it to access a soul sphere inside one of the Hell knight closets. (sector 1170)

Non-official
Inside of Secret #16, there is a misalignment on the western wall. If you shoot this misalignment, a door opens up into an easter egg room with an image of a human chest as well as the words "IT'S A CHEST!!!".

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.

Player spawns
This level contains four spawn points:
 * 1) facing west. (thing 334)
 * 2) facing south. (thing 337)
 * 3) facing south-west. (thing 421)
 * 4) facing south. (thing 614)

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

Technical information
Invisible platforms

At certain points in this map, enemies suddenly lower from the ceiling to the floor before being unleashed upon the player. This is achieved using Boom's "draw fake ceiling and floor" (action 242).

The monsters are positioned on a sector whose floor is raised far above the surrounding sector, with untextured lower sides. This sector shares a tag with a control sector outside the playable area, which has the same floor height as the surrounding sector. One of its lindefs is given action 242. This combination causes a fake floor to be drawn at the level of the surrounding sectors' floor, while the lower sides of the raised sector are not draw at all. In effect, this turns the raised sector into an invisible raised platform.

When the player crosses the trigger line, the raised sector is lowered normally with one of Boom's generalised floor actions. The monsters ride the lowering invisble sector down, thus appearing to be lowered from the ceiling.

Sequential action switch

The area beyond secret 11 requires a switch to be pressed three times in order to "deliver" an armor to an alcove. This uses a voodoo doll on a scrolling sector.

A voodoo doll is located in a scrolling control sector. Three sets of trigger lines are each blocked by a thin bump that is 25 units above the surrounding floor, just too high for the voodoo doll to step over. The switch itself is set to lower all of these bumps temporarily for one second. Thus, when the switch is pushed, the three bumps are lowered and the voodoo doll slides forward, crossing one set of triggers. However, before it can reach the next set, all the bumps are back up. The player must press the switch three times to have the voodoo doll clear all three bumps in the control sector, allowing the voodoo doll to cross all three sets of triggers and complete the sequence.

Inspiration and development
This level was originally titled Mill Assault. On June 27, 2011, Cohen renamed it to The Falls of Doom. On June 18, 2012, he changed it again to its final title, Downriver.