MAP05: Corrosion (1000 Lines 2 CP)

MAP05: Corrosion is the fifth map of 1000 Lines 2 - Community Project. It was designed by StormCatcher.77 and uses a MIDI rendition of the  theme by as its music track.

Essentials
As the level starts, instead of shooting the zombies around you walk off the starting platform to drop to the floor below, then head west until you reach a screen with "SYSTEM OFFLINE" on it - pressing this screen will lower the surrounding wall to reveal imps and demons guarding a shotgun, as well as lowering a pillar behind you with a chainsaw. Take the shotgun then return to the starting point to find that a lift has risen; ride it up then walk east to drop a structure which has various items on it, including the red and yellow skull keys. Kill any imps and shotgun guys that teleport in then press the platform in the middle of the structure to lower it and get a chaingun; lowering this platform also lowers a barricade on the east side of the hall, allowing you to reach a crossroads.

Red key
Head north from the crossroads to a shotgun guarded by a couple of imps, then continue north to a screen with "ACCESS DENIED" on it - pressing the screen will reveal a lost soul (or revenant on Ultra-Violence (UV) and Nightmare (NM) skill levels) guarding a second screen that also needs to be pressed. Pressing the second screen will lower two ledges behind you with imps and lost souls on them; get on either ledge then head west to an area with a water pool guarded by zombies, imps and a Hell knight. Flip the switch in the north-west corner to lower the dividing wall and reveal a second water pool with imps and lost souls, then step past it and flip a second switch on the north wall to lower the water and reveal a chamber containing armor bonuses and a couple of spectres.

Enter the chamber and press the striped north wall to lower a lift which will put you on top of the ledges surrounding the pools. Follow the path east and north to reach a chaingun which is guarded by two demons along with a cacodemon and a couple of lost souls; behind the cacodemon is a dark wall that you can press to lower it. Walk through the doorway to raise the dividing wall again then head straight forward to a pressure pad with a rocket on it; stepping on the pad will lower two pillars in front of you holding the red skull key and a rocket launcher, but when you drop down to get them more enemies will teleport into that area.

Yellow key
Lower the center platform that had the chaingun on it to lower the barricades leading back to the crossroads again, then head south from the crossroads to a metal wall that will lower as you approach to reveal a water pit. Drop into the pit and head south towards a pair of tan columns, which will lower a wall in front of you holding some enemies, then look east to see two streams - enter the south streams (on your right) and follow it until it turns north and terminates at an L-shaped step with a couple of tall lamps. Lower the lift between the lamps and ride it up to a gray ledge; from here you can get both of the remaining keys, but for now head north towards a super shotgun which is guarded by imps, zombiemen and a revenant. Approaching the super shotgun will lower the floor, revealing demons and cacodemons to the west along with imps and knights to the east.

Once the area is clear, go to the north-west corner to find some steps leading up to a chaingun guarded by another knight, then turn left at the top of the steps and walk forward until you see the ledge ahead lower. Get on this ledge and head to the north side to find chaingunners and a knight guarding some health bonuses - from here you can run south to leap across a gap and land on a ledge below, then continue forward to a green teleporter. Enter the teleporter to reach a new room and immediately move left or right to avoid the mancubus behind you, which will also cause the floor to rise; kill the enemies around you until the floor stops, then step across to the east ledge and follow the walkway anti-clockwise until you reach the south side. The walkway on this side will lower to reveal various enemies including an arch-vile - enter the monster closet and press the "SYSTEM OFFLINE" screen on the south wall, then go round to the north-west side of the room and get on the lift here to be taken up to another pressure pad. Stepping on it will lower two pillars holding the yellow skull key and a plasma gun; as before, when you drop down you will have to contend with more monsters that teleport in.

Blue key and exit
Retrace your steps as if you were going for the yellow key; this time, however, instead of dropping into the water pit where you collected the super shotgun, walk south-west to drop into a passage containing another super shotgun. Head west from here to another "SYSTEM OFFLINE" screen and press it, then go back the way you came and look south to see that a wall has lowered. Kill the enemies that teleport in then proceed south-east to a platform with a rocket launcher - the floor will lower to reveal an alcove containing a revenant guarding the blue skull key, but you will also need to dispose of some other enemies that teleport in to block your escape.

With the blue key, leave through the north-east or south-west doorways and follow the tunnels until they open up, then go south or west to return to an earlier part of the level; you will see that the south-east wall has lowered to reveal a lift that you can ride up to the exit area, but do not linger as a cyberdemon will shortly teleport to your location. Go west to an alcove with a revenant guarding a supercharge and press either of the vented walls on either side to lower them, then fight your way past some chaingunners and demons to a yellow column that you can press to open one of the exit doors. Now head north-east past the cyberdemon to a second alcove containing a megaarmor and lower either of the lifts on either side, then ride these up to a passage with imps and revenants guarding a red column that you can open.

Go back down to the floor below and drop into the water, then look north-west to see that a platform has lowered allowing you to reach the blue column which was previously out of reach. Arm yourself before opening this column as it will release two revenants that will teleport to the cages behind you (along with an arch-vile on UV and NM). Use the lift to get back up to the cyberdemon's platform then run through the now-open colored doors and go towards a shutter door in front of you - the level automatically ends when you reach it.

Secrets

 * 1) Pressing on the central lift with the chaingun lowers the barricades to the east, as well as a wall south of those barricades. That wall contains a backpack and medikits. (sector 96)
 * 2) At the north-east end, get on the northern lift, then run south to the teleporter. Instead of taking it, quickly run south-west to a lowered ledge that contains shotgun shells, energy cell packs and a berserk pack. (sector 94)
 * 3) On the outer walkway at the south-west end, you will find a supercharge. Run to it as the walkway lowers to get it. If you miss it, head north from this area and get on the small square platform with an energy cell, then head back to the walkway to get the supercharge. (sector 158)
 * 4) At the exit area at the south-east end of the map, there are two cages in the middle. Enter the north-east cage from the east side to teleport to a megaarmor. Attempt to leave and you will teleport to a supercharge. (sector 207)

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

The (absence of) data was last verified in its entirety on April 3, 2022.

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