E3M4: All the Marbles (Serenity)

E3M4: All the Marbles is the fourth level of Serenity. It was designed by Bjorn Hermans and Holger Nathrath, and includes a custom music track.

Walkthrough

 * Letters in italics refer to marked spots on the map. Sector numbers in boldface are secrets which count toward the end-of-level tally.

Secrets

 * 1) Directly south of the first room is a concave wall. Open the middle of the wall east of this area to find a plasma rifle. (sector 11) Press the skull on the wall to reopen the door if it closes before you leave.
 * 2) The door used to access secret #1 also counts as a secret. (sector 12)
 * 3) The passage to the teleport pad leading outside counts as a secret. (sector 54) It is lined with nine health bonuses.
 * 4) The teleport pad in secret #3 is also considered a secret. (sector 53) It is thus unreachable, as there is no way to step onto the pad without teleporting away.
 * 5) The passageway containing the switch which allows access to the yellow key is flagged as a secret. (sector 102)
 * 6) The space directly in front of said switch is also marked as secret. (sector 101)
 * 7) The first, unlit space of the passageway to the E room counts as a secret. (sector 127)
 * 8) The lit portion of the passageway to the E room counts as a secret, too. (sector 128)
 * 9) The cage from where the imps attack you in the passage to the E room is also marked as a secret. (sector 125) There is no way to enter the cage, and so this secret is unreachable.
 * 10) The pit that the passage to the E room curves around also counts as a secret. (sector 131) Press the wall at the south of the pit to raise the floor and escape. On skill 4 or higher, you will find two boxes of ammo here. Note that on skill 3 or higher, you may have trouble entering this secret, as one half of each opening into the the pit is blocked by a barrel.
 * 11) The window immediately south of secret #10 counts as a secret. (sector 175) It cannot be reached, as you can neither climb nor fit through the window.
 * 12) The room seen behind secret #11 counts as a secret, as well. (sector 174) It is likewise unreachable, as there is no way to enter the room.
 * 13) The E room counts as a secret. (sector 130)

Bugs
Engine versions prior to v1.666 can display a minor HOM as the red door is opened.

Four of the secrets are unreachable; as a result, only 69% Secrets is possible.

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

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

Inspiration and development
An early version of this map appeared as E2M2 of the collection "Nathrath's Fab Four" (NATHRATH.WAD).