E3M8: Dis (Doom)

E3M8: Dis is the final map of Inferno in Doom. It features a boss battle with the Spiderdemon (also called the Spider Mastermind). Dis is named after the capital city of Hell that appears in the "Inferno" section of Dante Alighieri's epic poem The Divine Comedy. It uses the music track "Facing The Spider".

Walkthrough
To complete this level, the player must kill the Spiderdemon, who is the Boss of the episode.

She appears on the bottom right 'clover leaf' of the map with a baron of Hell (on harder skill levels) in the top left leaf and two cacodemons occupying the other corners of arena. Almost all ammo is on a raised walkway above the main arena containing mostly of single rockets and a few cells (B), except for the plasma gun, which is in a small room in the center of the map (C). The only way to access the walkway is from a set of steps to the north of the central building, or by walking along the walkway upon entering the level. This lack of ammo provides extra challenge and you are vulnerable to the spider's hitscan attacks. Outside as there is barely any cover (except for the thin pillars of the circular room where the plasma gun and megaarmor is located), to protect yourself from the spider's bullets, moving quickly is key to survival here. There are no health items here, so make your health count!

An effective strategy for this level is to deliberately cause the other monsters present on the level to attack the spiderdemon. The spiderdemon will then become preoccupied infighting with the other monsters and will ignore the player's fire until the attacking monsters are killed. For example, you can move behind a cacodemon, and the spider will try to fire at you, but will fight the cacodemon instead. Fire at the spider from behind the cacodemon, but do not fire at the cacodemon itself. Eventually, the spiderdemon will kill the cacodemon, but the combined forces against the boss will cause it to die faster (see demo below). This method is a good way to distract the spider in battle so you can collect the ammo that is sitting the outer ledge. As a consequence of the extra ammo and monster respawning of Nightmare skill, this is one of the few levels that is generally easier in Nightmare mode than on Ultra-Violence.

The level is particularly easy if you have accumulated an arsenal from previous Inferno levels, only the shotgun will have little use due to its short range. If you have a BFG9000 and extra cells from the previous levels, fire the BFG at the spiderdemon point-blank before it has a chance to retaliate, which will kill it in a single shot. You need to make sure you fire the BFG standing immediately next to the demon, or else you might need more shots.

Official
There are no official secrets in this level.

Non-official
The small circular room in the middle of the arena contains a Plasma Rifle and Combat armor (note that the doors won't automatically close once they have been opened). Take note that once you enter this room, any doors you have not already opened manually will open automatically, leaving you open to the boss.

Bugs

 * Nineteen rockets (Things 35-53) have no flags set for any of the difficulty classes, so they do not actually appear in the level.
 * Sector 1 is unclosed, as the front sidedef of linedef 21 and the back sidedef of linedef 57 reference their own sector (sector 2) instead of sector 1. This second sector references tag 6, which doesn't exist elsewhere in the map.

Trivia

 * Dis is the city comprising the lower circles of Hell in Dante's Inferno.
 * Dis was also an ancient god of the underworld.
 * Many people in various Doom forums on the internet have claimed Dis to be their least favorite or the worst level in Doom, due to its simplicity compared to earlier levels in Inferno.
 * The music for this level is inspired by the track "Sargent D & the S.O.D." by Stormstroopers of Death.

Records
The Compet-N records for the map are:

Demos

 * [[Media:E3M8 Spider Infighting.lmp | E3M8 being completed by exploiting monster infighting]] (file info)