MAP20: Waves of Darkness (Resurgence)

MAP20: Waves of Darkness is the twentieth level of Resurgence. It was designed by Josh Sealy (Joshy) and uses the music track "Heartbeat" by Stuart Rynn (stewboy), composed specifically for the level. The map is inspired by the maps by Speed of Doom co-author Darkwave0000, whose name is also referenced in the level's title.

Other points of interest
The map contains a dark room in the northernmost part of the map, near the bridges where you fight two extra cyberdemons that spawn from the floor. The only purpose of this room is to trick you into believing there is a quick escape from the fight by using the red key, this is definitively a unique feature of this map.

SPOILER: This room is indeed the start sector from MAP21.

Secrets

 * 1) Sector 249: In the southeast corner of the map, you can find a button tucked behind a crate. Push it, then go as if you were heading for the red key. Look north just before the red key to spot an open hall, where you can get boxes of rockets and a soul sphere.
 * 2) Sector 267: In the super shotgun room directly west from the starting point, flip the switch to lower the barricade to the north. Move across this barricade to the lift, where flipping the lift switch lowers it to the next floor. Instead of flipping the switch to go back up, try flipping the same switch you did before (where its general location would be) to lower yourself to a secret with a BFG9000.
 * 3) Sector 475: Open the yellow bar and go northeast to the place where you are supposed to jump to the blue bars. Instead of jumping there, jump straight north to the rocky ledge that had imps on it. Drop into the nukage collecting boxes of rockets and go along this nukage to find a soul sphere.

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

Last updated on 3 July, 2015.

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