Diopatra

Diopatra is a single-level PWAD for Doom. It was released in 1994 by Eddie Nguyen, and is the third in a series of single-level wads, following UCA and Talpoida and preceding Sapidus.

Secrets

 * 1) In the room immediately north of you after descending the first staircase, one of the torches is green instead of red. Behind it is a secret door into a tunnel which leads to a shrine. (sector 70) Two boxes of ammo, a box of shells, and an energy cell pack can be found inside. If you jump down to collect the cell pack, you can escape by following the river of lava to a secret door to a hidden lift leading to secret #2.
 * 2) In the hallway with the brown, cobblestone floor nearby the first room, there is an inverted cross on the east wall. The middle section is a secret door locked with the red key (sector 80) into a room containing two health bonuses and a backpack. While this secret can be accessed through the lift from secret #1 without a key, the secret door must be traversed for this secret to count.
 * 3) After collecting the yellow key, open the yellow door behind the switch-activated door north from secret #2 and press the switch on the wall. This opens a nearby doorway (sector 93) into a slime pit with a supercharge. However, this is an inescapable booby trap that will slowly kill you, unless you also press the button in the compartment found midway through the sewage tunnel to the exit. If you intend only to collect the secret, you can step into the doorway without jumping in, and then back out.
 * 4) In the slime cavern in the northeast, you can collect this secret by stepping on any of the following: the darkened middle point of the collapsing walkway; the darkened portion of the island behind the southern wall with the box of ammo; or the passage in the southwest that contains two medikits, an energy cell and a radiation suit. All of these are considered a single sector (sector 27).

Bugs
Various rivers of lava in the cavern (sector 45) and the red circle in the northwest (sector 38) have sector effect 11, a 20% damage floor which harms you through the radiation suit, as intended by designer Eddie Nguyen. However, this also ends the level when your health drops under 11% (as on E1M8), meaning you can finish the level by jumping into the nearest patch of cavern lava you can find.

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

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