Video-Vergleich verschiedener Versionen

 This first one's an interesting one. The line outside of the secret door was originally a repeatable
 open-and-close door. The main reason this line is a door is because a Deathmatch player spawns in this
 outdoor area. It was changed in v1.1 to a one-time door open most likely due to what you see in this
 video.

 Changed from v1.0 to v1.1 was this pit. The switch was moved to the bottom of the pit while the pit
 itself doesn't rise when you walk in it. Combined with saving and loading, you can create some
 interesting effects, like making it rise faster while changing the texture, lowering the floor back
 down, and one particular random occurance that happens in this video.
 --
 Shortly after I posted the last DOOM Historic video, I realized that I forgot to put in what happens
 when you walk-in + save/load + walk-in again. Not much difference. But if you walk-in just after it
 stops, it can rise again, up to the sky.

 E1M8 had two changes involving the final exit teleporter.

 The first, shown in this video, is that the lines in the teleporter exit (8 lines, 2 on each side due
 to splitting up the sectors because of splitting up the floor textures in this giant teleporter) have
 one-time usage. This would make sense, since when you cross the teleporter, you'll slowly end the
 level. You would never have to noclip back and cross it again. But what makes this a pretty noticable
 glitch is when you play it in multiplayer. Player 2 might want to cross the same line as player 1.
 Doing so will reproduce this bug. It was changed to repeatable use in v1.1.

 The second, not shown in this video, is that the lines surrounding the player after crossing the
 teleporter is a 64x64 square, while on v1.1 and up it's 96x96. Why does this matter? Again, multiplayer.
 It was increased so that player 2 doesn't easily telefrag player 1 and "ruin the moment". (Not sure if
 telefragging would break this, haven't tested it)

 Also notice some early DOOM behavior. The health maximizing at 199%. IDKFA not giving you any health
 (there is a soulsphere in this level, remember?).

 And IDSPISPOPD... not so easy to type fast.

 E1M1 has a small bugfix and a new secret. The bug is trivial: there's a stimpack outside the armor
 window. As for the secret, it's the elevator with the armor bonuses and the shellbox.
 You probably know that E1M4 had a swastika in it that got changed at a later version. But what you
 didn't know was that the original swastika was left-faced. Then it got changed to the familiar
 right-faced swastika.

 E1M5's invincibility secret was also added in v1.2. Notice that the sphere makes the item pickup sound
 instead of the iconic sphere sound. This also applied to the soulsphere.

 v1.666, DOOM 2's original engine, made a lot of improvements to the EXE itself. One of them is the sound
 code. Although the quality is improved, we get a tradeoff of a monotonous pitch. Both v1.2 and v1.666 in
 the recording were set at their maximum volume.

 The change in the maps between v1.2 and v1.666 happen in 5 levels, E1M4-E1M8. (ED: 6 levels, including
 E1M2) Notice some things like how you don't have negative frags for nukage death in v1.2, the sphere
 sounds were added in v1.666, and how a soulsphere will set your health to 199% in v1.2.

 E1M4's biggest change was the swastika. From v1.1, it changed from left-faced to right-faced, and now it
 changes to some random thing. There's also a rocket box that moved down to the exact middle and another
 rocket box (not to mention a former human and a former sergeant) that moved out for accompany the
 change. E1M4 also moved the deathmatch start in the blue armor ledge down below the ledge. Why? Because
 that elevator does not go down, meaning that in "altdeath" mode, whoever spawns up there gets the
 powerful blue armor. Broken.

 E1M5 also moved a deathmatch start. This time from the secret soulsphere area (instant max health? heh)
 to the secret invisibility area. E1M5 also changed the yellow key window around, removing its
 "impassability" and lowering the floor.

 E1M6 removed the hard former sergeant that spawned outside of the level (Also noted in the DOOM
 memorabilia page) and changed the floor of the side yellow doors to match the adjacent floors. E1M7 made
 the door right before the exit door (the one you activate a switch to open) openable from the other side
 because of the deathmatch spawn there. Don't want this player getting stuck. =)

 E1M8 changed the computer map on the bottom-right part of the "star" to a shotgun and added a secret
 door on the right inside side of the Baron rooms, leading to a switch that activates the lift before
 the Baron encounter. The vertex between the left and bottom-left part of the outside of the star has
 been tweaked, but I'm not sure why that's done. (Rendering issues?)

 Also, there is no change in the maps between v1.666sw and v1.9sw. So this concludes the changes in
 the maps between the shareware versions.

 There's only one map that's changed between registered v1.9 and Ultimate... E1M1. You might have noticed
 the new secret that leads from the start to the outdoor area. That was an Ultimate thing. There are some
 multiplayer additions too. In the far-left corner of the start with the armor bonus, that armor bonus is
 moved away from the corner just a little. In multiplayer, there are three barrels surrounding both that
 and a new shotgun. Also in multiplayer is a new berserk pack that only shows up on Hurt Me Plenty and
 easier next to the left pillar towards the green armor.
 Oh, and the outdoor deathmatch start is moved slightly away from the wall,
 but where's the significance in that?

 Now to compare DOOM II versions v1.666 (dated 8/29/04) to v1.7a.

 The first change is in MAP02, where the door bars in front of the left former sergeant was removed.
 Probably because it confused some players. (This was a door? Huh?) It was replaced with a "block
 monster" line that traps the sergeant in that room. That line was also added in the red door room. Also,
 some sectors had the same tag as the blue door. This was never noticed because the blue door line only
 opened the sector behind it.

 MAP14 raised the beginning crusher waterway (with rocket launcher) by 32 units. This is most likely due
 to stopping the crusher in a height that players can't walk through. This does cause a missing texture,
 as the video will point out. The door trigger from the middle waterway lift+door combo was moved away
 from the lift trigger. Not completely sure why.

 MAP15 removed a former human. Not sure why.

 In MAP17, the archvile pit teleporter now teleports to the middle piller rather than the left caves
 (which is multiplayer only, so the teleporter did nothing in single player)

 The original MAP18 had a MISSING LINE. Not a texture, an entire line. At least MAP24 fixed only missing
 textures. (In the red keycard room. I guess they always went through the teleporter during testing.

 MAP25 had the most changes. (Though not the biggest impact) The biggest change is that the revenant
 blood pillar lift is now activated from all sides, rather than the one closest to the elevator. Speaking
 of the elevator, the texture was changed from the tan stone to the gray stone. (No more "This was an
 elevator? Huh?" moments) The sector on the front side of the blue door now blinks light in 1 second
 intervals. The rocket secret near the Megasphere (EDIT: Actually the plasma pack secret, as the rocket
 launcher doesn't show up in ANY difficulty. heh) had some changes, such as the secret itself adding
 towards the secret total. Three lines in that room have been changed to match adjacent lines. (There's
 also some changes to back textures on lines that doesn't really show back textures, no idea why.) Last,
 the BFG secret area counts toward the secret total. And the other side of the BFG secret door was
 changed to the "secret" wall flag. (Turns red during automap. No idea why, as they changed the
 wrong side)

 MAP28 is not in this video because it's all deathmatch spawns. Three new ones and one in the scrolling
 "snake spine" room moved slightly. No idea on the latter one.

 MAP29 is probably the biggest change of all. No spoilers. Just enjoy. =)

 DOOM II v1.7a to v1.9 map changes.

 MAP01 and MAP02 has some of the biggest changes between DOOM versions, though you might not know it. The
 entire level was shifted towards the center point. (0, 0). And while the level was intact, most of the
 things got shifted around. This shifting causes some well-known map02 sergeant bugs. I wonder how
 Deathmatch compares between v1.7a MAP01 and v1.9....

 MAP03 has a new secret passageway. You activate it by going through a hidden line before the left blue
 door switch, then going all the way back to the beginning. You get a backpack and, in multiplayer, a
 super shotgun. Also, the big wall next to the destination (after you go up the stairs) is misaligned for
 some reason.

 In MAP05, the area leading to the blue armor secret was a bit of a puzzle. It starts closed, then by
 going through the beginning-to-dark lift, it opens. Then going to the area closes it. Then you open it
 by activating a switch in one of the rooms. This sounds good. However, in v1.7a, going through the
 doorway to the blue armor ALSO closes it. If you activated the switch beforehand, the door can no longer
 be opened, and you have to go through another not-so-obvious passage. Also, in v1.7a, you can't go back
 up the beginning-to-dark lift once you go down there. Apparently some people are not manly enough to
 handle imps in a dark room. Har.

 MAP11 had a hard-difficulty arachnotron stuck in the wall. That was fixed, along with a change in the
 rocket switch platforms that makes it easier to go to the backpack platform.

 And then no real changes for the rest of the maps except the secret maps. MAP31 and MAP32's secret maps
 (which consists of MAP31's BFG secret and MAP32's 4 pillar and 2 wall secrets) now count towards the
 secrets total. That's it.

 I probably should have done v1.7a to v1.8 and v1.8 to v1.9. However, I forgot that there was an update
 patch from v1.7a to v1.8.

 The only maps affected by this update were MAP01 and MAP02, where the entire level was shifted and most
 of the things were shifted around. Sound familiar? Actually, this process happened TWICE with different
 positions. This introduced some comical bugs. For example, MAP02 had sergeants trapped behind walls.
 'Nuff said. All but the barrel sergeant were fixed.

 The plasma gun in MAP01 was shifted down 8 units from the center of the sector. What does this mean?
 There's an oldschool MAP01 trick where you "plasma bump" the sector at a certain angle and grab the
 plasma gun without having to ride up the elevator and jump down at it. In v1.8, the plasma grab was
 easier. (Though you still needed to walk to it at a certain angle)
 The v1.7a to v1.9 video actually consist of all the differences between v1.8 and v1.9.
 Sorry about that.