Episode 4 as update for registered Doomid Software released a free patch to upgrade registered Doom v1.9 to Ultimate Doom.
When asked "who's the guy responsible for Ultimate Doom (...) in fact why did they make an ultimate Doom", John Romero had this to say:
"Actually the decision to create Ultimate DOOM was brought up by me but it was going to happen eventually.(source: rome.ro)
You see, every id Software game was released as shareware, then at some point down the line, we would release the registered version into retail stores (where previously you could only purchase the full registered version over the phone).
Ultimate DOOM was the retail version of DOOM, but with an extra episode. I thought that we should create an extra episode and give the buyers more value, so Episode 4 was born. I had several people creating maps for the episode, which is why the consistency isn't there like Episode 1.
And the 4th episode was supposed to be VERY tough, which is why we had lots of outrageous names for the levels. We were putting together the 4th episode as early work on Quake was happening and I was busy doing executive producer work on Hexen."
According to John Carmack, The Ultimate DOOM "was never a real focus at id", which is why there wasn't a new end boss, among other things.
[Source: John Carmack Interview (Doomworld.com)]
The revised version of the map E1M1 in The Ultimate DOOM contains 666 sidedefs.
A sidedef contains the wall texture data for each linedef, while the linedefs themselves are what make up the "shape" (for lack of a better word) of a map.
666 is, of course, the Number of the Beast.
In the first level of the fourth episode, it is possible to lower a platform, and as such uncover the logo of the band Nine Inch Nails: "NIИ". It's interesting that the music of the next id Software hit, Quake, was written by the band's frontman Trent Reznor.
All level names of Episode 4 (with the exception of the secret level) were taken from the following passages in the King James Version of the Bible:
- Thy Flesh Consumed
Proverbs 5:11 - And thou mourn at the last, when thy flesh and thy body are consumed
- E4M1: Hell Beneath
Proverbs 15:24 - The way of life is above to the wise, that he may depart from Hell beneath.
- E4M2: Perfect Hatred
Psalm 139:22 - I hate them with perfect hatred: I count them mine enemies.
- E4M3: Sever The Wicked
Matthew 13:49 - So shall it be at the end of the world: the angels shall come forth, and sever the wicked from among the just
- E4M4: Unruly Evil
James 3:8 - But the tongue can no man tame; it is an unruly evil, full of deadly poison.
- E4M5: They Will Repent
Luke 16:30 - And he said, Nay, father Abraham: but if one went unto them from the dead, they will repent.
- E4M6: Against Thee Wickedly
Psalm 139:20 - For they speak against thee wickedly, and thine enemies take thy name in vain.
- E4M7: And Hell Followed
Revelation 6:8 - And I looked, and behold a pale horse: and his name that sat on him was Death, and Hell followed with him. And power was given unto them over the fourth part of the earth, to kill with sword, and with hunger, and with death, and with the beasts of the earth.
- E4M8: Unto The Cruel
Proverbs 5:9 - Lest thou give thine honour unto others, and thy years unto the cruel
The Steam download version of the game is listed as Windows 2000/XP/Vista platform because the executables are modified to use a DOSBox variant (v 0.70); additionally the traditional setup.exe is missing.
Is confirmed that neither Valve or id Software contacted the DOSBox project staff and initially the game didn´t includes the TXT´s that must be present under the GPL license (so they failed to fulfil 2 points of the GPL license).
2 days after the launch, there was an update that includes COPYING, AUTHORS and THANKS .txt of the DOSBox 0.71
In April 2005 a full port of this game was brought to XBOX as part of the Doom 3 special edition.