Corridor 7: Alien Invasion TC

As the hint message states, you can disable/re-enable light levels and coloured lighting at will, however you can only disable flats.

Enabling/disabling lighting and coloured lighting and disabling flats is trivial in Doomsday; the same very basic XG def's can be used for every map. Re-enabling the flats in Doomsday 1.8.6 would have required a unique very messy and very massive def for each map to change each area to the right flats. I concluded it simply wasn't worth it.

The latest Doomsday beta's have new XG options that would make it much easier to do; with the new features, I could make a single, still massive def, that could work on every map.

I am aware of the small border of HOM's around the top's of the walls where the sky was on Map01; the reason it happens was an oversight by Deng team that fortunately doesn't occur on sky sectors on any other map in Corr7TC.

I'm considering moving those switches to external add-ons for the standard mod release; you select the add-on in Snowberry (like you can select models by group with the JDRP) before you launch the TC.

This would mean you would have to quit and relaunch the TC to toggle the add-on's (but to make it clear enabling/disabling them wouldn't break any in progress game). It has been suggested to me that most users will disable say, the flats, on every level, making pressing the switch each time, a chore.

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Have come across a bug. Sometimes the game will freeze if you open particular doors.

Sometimes I get this in the notepad document that appears (When the game doesn't just freeze completely but actually drops out):

GL_ClearRuntimeTextures: 0 detail texture instances.
GL_ClearRuntimeTextures: 0 detail texture instances.

And in a window I get "Segmentation Violation."

IT only seems to happen on doors that once opened stay opened, not on doors that close behind you.

This has happened on level 21, 25 and 28. All alien levels. (The crash on level 28 was caused when I opened some (but not others) of the health chamber doors at the start. On level 21, it occurred when I opened the red doors with the 6 red lights in a circular layout on them. And on level 25 it was a green textured door

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What are you trying to pull with this \"custom\" version of JDoom? My norton said it was a virus!

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bloodmartyr_x said:

What are you trying to pull with this \"custom\" version of JDoom? My norton said it was a virus!

Likely a false positive, you have nothing to worry about. Norton is known for being crap.

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KiiiYiiiKiiiA said:

And in a window I get "Segmentation Violation."


There’s a bug in 1.8.6, that the XG class used for those doors (the health station, alien doors) can, extremely rarely, corrupt all XG on the current level. Hence the ultimate safety net, is to save at the exit of the previous map, rather than the start of the current map.

It might have been fixed since, but other parts of XG have been broken in the 1.9 betas, due to the rewrite (in the grand scheme of the Dday 1.9/2.0 beta’s, maintaining map based modding features are understandably a low priority), making running a DDay map based mod on them a pointless exercise.

bloodmartyr_x said:

What are you trying to pull with this \"custom\" version of JDoom? My norton said it was a virus!


I can assure you that there is no malicious code in Dday 1.8.6 as far a I know, or Corr7TC. Many Doom source ports seem to trigger false positives from virus software for some reason (one can do forum a search for threads about so and so port triggering them).

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Vermil said:

There’s a bug in 1.8.6, that the XG class used for those doors (the health station, alien doors) can, extremely rarely, corrupt all XG on the current level. Hence the ultimate safety net, is to save at the exit of the previous map, rather than the start of the current map.

It might have been fixed since, but other parts of XG have been broken in the 1.9 betas, due to the rewrite (in the grand scheme of the Dday 1.9/2.0 beta’s, maintaining map based modding features are understandably a low priority), making running a DDay map based mod on them a pointless exercise.


Yeah it wasn't a big issue, as when I am 'playtesting' stuff (not that I am an official playtester of this or anything, but just having that mindset), I save everywhere. But I thought I would mention it just in case. Heh, there's nothing I have mentioned so far that you haven't already been way ahead of me, but you never know.

Thanks Vermil and everyone involved in this TC, this has been a lot of fun. Something very different. Oddly enough, playing through this TC has made me think a lot about Doom mapping. Because of the simplicity of the level design (no variation in floor heights etc etc) this means that monsters can follow you anywhere on a level. There is no safe place on these levels, nowhere that a monster cannot access. Once you unlock an access door, then from that point, all the monsters can open it too. This TC had a real sense of tension. And it has got me thinking how to implement something like that in a Doom map.

So I finished the 30 odd maps here. Maps 32 onwards, these are secret levels which I gather I missed? There does seem to be a lot of secret content that does not appear in the normal campaign. New monsters, new objectives, new graphics. There seems to be a lot I missed out on.

Couple of points I will mention, just for completeness.
-IDCLEV'ing to every map beyond 30 takes you to the previous level. E.g. warping to map 31 takes you to map 30, warping to map 32 takes you to map 31 etc etc.
-I am really not sold on the lag with the assault shotgun. Ok I can see why you have done it, it does force you to be much more tactical in your use of that weapon, but it sure doesn't make it satisfying to use.

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KiiiYiiiKiiiA said:

Thanks Vermil. Yeah it wasn't a big issue, as when I am 'playtesting' stuff (not that I am an official playtester of this or anything, but just having that mindset), I save everywhere. But I thought I would mention it just in case. HEh, there's nothing I have mentioned so far that you haven't already been way ahead of me, but you never know.


It's just the knowledge of the abilities of a port, that one get's from modding for it.

I'd imagine that someone who has made a mod for ZDoom would know the in's and out's of ZDoom's abilities and behaviour to a degree that would bamboozle me.

But obviously, I welcome any feedback on the TC, bugs or game play as I probably missed loads of things (i.e a second set of eyes can find many things one misses).

KiiiYiiiKiiiA said:

There is no safe place on these levels, nowhere that a monster cannot access. Once you unlock an access door, then from that point, all the monsters can open it too. This TC had a real sense of tension. And it has got me thinking how to implement something like that in a Doom map.


That is exactly what I tried to design Corr7TC's game play to be like; make the player feel like they were the hunted, without making the player weak or unable to defend themselves.

Corr7’s level design lends it’self to this, though at the cost of some of the uniqueness of the individual maps.

Though Corr7 itself didn’t leverage this style of game play; instead the game arguably, in-avertedly, made the player feel like they were the hunter, hunting the aliens.

KiiiYiiiKiiiA said:

So I finished the 30 odd maps here. Maps 32 onwards, these are secret levels which I gather I missed? There does seem to be a lot of secret content that does not appear in the normal campaign. New monsters, new objectives, new graphics. There seems to be a lot I missed out on.


I suppose I can mention such things now, given that the TC has been out for so long; on Level 30, you can either destroy OR enter the Vortex; doing the former gives you the ending from the Disk version of Corr7 while the later takes you to the CD maps (Levels 31-40).

Hence why the mission objective on Level 30 is "do what ever is nesscerry" rather than explicity stating "destroy" or "enter".

There are 6 secret levels in Corr7/Corr7TC, accessible from Levels 1-30).

KiiiYiiiKiiiA said:

-IDCLEV'ing to every map beyond 30 takes you to the previous level. E.g. warping to map 31 takes you to map 30, warping to map 32 takes you to map 31 etc etc.


There are two slightly different variants of Level 30, based on wheter you complete or skip Level 29. For plot reasons.

KiiiYiiiKiiiA said:

I am really not sold on the lag with the assault shotgun. Ok I can see why you have done it, it does force you to be much more tactical in your use of that weapon, but it sure doesn't make it satisfying to use.


I agree. It was the best I could do to balance the weapon, within the limits of Dday 1.8.6's modding abilties.

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Looking back at this TC; the above recent unexpected interest in it, got me thinking about it again:

I was surprised at how popular it was. It wasn't an original TC, creation or anything.

I didn't receive allot of feedback stating exactly what was good and bad, but the amount of comments I received stating that the TC "was better than the original game" or "I've never played the original, but this is fun" mean I must have done something right, at for the first half of the game anyway because obviously, I don't know how many people played it for more than few maps or all the way through.

One thing I would notably criticize about the original Corr7 is that it makes the player feel like they are the powerful hunter; you are suppose to be alone and outgunned in a dark and alien infested base! With Corr7TC I tried to make the player feel like they were the hunted, without making them weak (i.e. the player is more than capable of defending themselves). I tried to achieve this through surprise rather than giving the aliens high health, instant kill attacks or overwhelming the player with sheer numbers (though many maps in Corr7TC do coincidently feature almost double the bad guys they did in Corr7); that the aliens were often moving around the map and/or leaping out at you from places and directions you thought safe. I found that Corr7's level design was naturally suited to this and am surprised that Capstone didn't leverage it.

I'm pretty pleased with the full range of bad guys and weapons; I believe I gave most bad guy's something, though admittedly very small in a couple of cases, unique and gave most of the weapons a potential use (certainly many many times more than original game anyway). The main weapons are the M-343 and Dual Blaster with the Plasma Rifle and Assault Shotgun providing heavy fire power. The Assault Cannon usurps the Dual Blaster as in the original game and the Disintegrator is the ultimate weapon. Maybe I should have tried to give the Disintegrator a new behaviour in Corr7TC instead of bringing it over largely as is though; it was never really a useable weapon in Corr7. Essentially a BFG (near all of Corr7's weapons are clones of Doom's weapons), it's pretty redundant against the games small numbers of primarily medium health foes in mostly cramped areas. Still it only appears once in both Corr7 and Corr7TC, right near the end of the game and I can't really alter it much with the available actions any way.

I would have liked to have given the final boss, Tebazile (a.k.a Elizabeth) a more interesting attack, but I mostly ran out of available actions. Though I suppose the slightly unique set up of the arena you face him in makes up for it. I would have also liked to have used the CD bad guys more; In Corr7 itself, two of the three CD map bad guys, the Semaj and Unknown Alien were very barely used. I ended up using them about the same; perhaps because I gave them movement patterns in Corr7TC that weren’t really suitable for cramped areas (Indeed, they ended up being the only two aliens with "unusual movement" because near none of the Disk map layouts would remotely support bad guys with non-standard movement; I planned the behaviour of the bad guys somewhat around the maps they were mainly in. I was too pleased with the erratic movement of the Semaj to change it and the Unknown was a bit of a silly bad guy in the first place; a tiny little alien in power armour with a big gun that comes out of his chest. Make him fast and it's predictable. Turn him to some high health high attack mini-boss and it's cheesy that the little guy is potentially the most deadly. I ultimately went with the former as Corr7 already has three mini-boss like bad guys. In hindsight, with Corr7TC I perhaps should have brought in a non-hitscan firing foe earlier than I did (i.e. map number wise).

I admit that I would have liked to have come up with some more objective types though (not so much in what the player has to do to achieve the objective, but the illusion of doing something different plot wise). Indeed, shortly after the last release of the TC, I actually changed objectives on a couple of maps for this purpose. The design behind Corr7TC's objectives was to bring the games plot into the game; almost every mission objective type in Corr7TC is based on something insinuated in the manual's plot or bad guy descriptions (this also guided a couple of the behaviour tweaks made to bad guys).

One thing, looking back, the one thing I regret not really doing more with the levels themselves; the layouts of the original maps, the objectives I added to them, the game play I tried to make in them, all mostly fine in my opinion, for Levels 1-30.

I rebuilt Levels 31-40, the "Alien World" maps (that's what I interpreted them as being; the original game has no plot for them) in an attempt to both improve them and also to make them more cohesive as a group. In the original game, they come across largely as 10 individually isolated levels in an unknown place or places and were a notable step down in quality compared to Levels1-30. You can see Capstone's mapper (Corr7's credits only list one mapper) had a vision for them, but the end result was not particuarly good looking or fun.

This may sound arrogant, but I believe I improved upon the original Levels 31-40 on all above counts while keeping the vision of the original mapper. Though I still consider them weaker maps than Corr7's Levels 1-30; I had some difficulty trying to mimic Corr7's very unique map style (I can't recall a single Wolf3D or Blake Stone map done in a style like Corr7's maps). Not helped by the fact that I saw the visual themes used on the original Levels 31-40, largely carried over into my rebuilt versions, as a letdown after Levels 20-30's atmospheric visual themes.

Perhaps the most notable level thing I feel I should have done, is reworked Levels Levels 20-30. I don't mean rebuild them like I did with Levels 31-40 as such, (though in Corr7TC I did rebuild Level 29, retexture Level30 and make a few little layout tweaks to a couple of the others) but rather re-organize them and/or give the three visual themes used in them a real purpose; Levels 20-30, "the converted floors" (i.e. the part of the Human Base converted by the aliens) feature three visually unrelated themes with no obvious pattern to their order or function given by the games plot. Indeed, they go Red, Red, Green, Green, Red, Green, Red, Yellow, Yellow, Red, Yellow; the colours are how I reference the three themes, based off their primary colour; the Red theme is literally all Red, the Green literally all Green and the Yellow er, Grey with notable Yellow lights.

I came up with two real ideas for re-organizing the converted maps in Corr7TC while working on the TC; I noted that in terms of how converted the maps layouts looked, that the Red maps were the most human shaped, then the Yellow and then finally the Green. Interestingly the end game cut scene for the Disk version of Corr7 actually shows Level30 decked out in the Green theme, despite that it used the Yellow theme in game (as mentioned above, I retextured Level30 in the Green theme; I did it so it matched the end game cut scene; you might also notice that the yellow wall and white ceiling lights I added in Corr7TC were inspired by details in that cut scene).

The other idea I came up with for re-organizing the converted maps was to give each theme a purpose in the plot; Red was to be Biological, Green Tech and Yellow Construction with suitably themed objectives; I interpreted a couple of textures in Red and Green themes as potentially fitting these. Yellow, I admittedly initially struggled to think of what it could resemble.

For multiple reasons and thoughts though, I ended up not implementing either of these; I was concerned that each theme would end up with an essentially isolated plot (not good when each theme only lasts three-four maps and even worse if all the levels from each theme weren't re-ordered to be next to eachother). I was concerned about if I wasn't already going too far by rebuilding Levels 31-40. There also wasn't the resources in Corr7, very notably Yellow theme, which I actually considered simply getting rid of there was so little of it; all three alien themes share the same computer mobjs. As mentioned above the vast majority of the textures in each theme also didn't suggest a purpose or function (i.e. what is a wall of scrolling tube lights suppose to be).

Something else I considered was having the last few Human Maps slowly transform into the Alien ones; in the original Corr7, Level19 was completely Human and Level20 completely Alien. In Corr7TC I animated the textures of Level19 to
represent the level being in mid change (and mission objectives I added alluded to the aliens converting the base). But It would have been interesting to have gone further with this actually mix the alien and human themes into a map
across several levels; maybe a spoiler, but I ended up doing that to a degree with one of the rebuilt CD maps in the TC. But I was concerned about spoiling the converted themes in advance and concluded that Alien Yellow wasn't different
enough in colour (i.e. visually) to the Human theme, Alien Green wasn't suitable for representing mid conversion and the Alien Red converted maps weren’t different enough in layout to truly emphasize the different in a half Alien half
Human map. I would have had to rip up the converted maps to make them look somewhat like my vision of a half Human, half Alien map.

Reading all the above level stuff back, I actually believe a combination of it all (i.e isolated the above ideas may not have been good enough or badly stuck out, but merged together...) could actually have been pretty neat. But then as I stated above, I regret not trying to do more with the levels.

I perhaps also should have divided the Human Base texture theme used on Levels 1-19, into two groups and retextured Levels 1-10 in one group and Levels 11-19 in the other. To deal with the fact that Levels 1-19 use the same visual theme.

I also wonder what it would have been like had I come up with a set of completely or largely unique game play features for the Alien half of the game; In the original game, there were no new features introduced in the Alien half of the game besides teleporters on Levels 31-40. The Alien maps also didn't have a bunch of the features from the Human half of the game making them simpler (the Alien level layouts were also simpler than the Human maps); there were no locked doors for instance and ammo/health dispensers only appeared a couple of times. In Corr7TC, I added a couple of small new game play features to the alien maps; a simple oxygen system (no armour and you very slowly take health damage; armour in Corr7 is strangely a spacesuit) and on the Alien World maps, force fields to function as locked doors.

But I couldn't think of a large number of suitably different, but similar that would fit in a largely un-interactive run and gun FPS (by which I mean we weren’t talking about Deus EX style interactions); make them too different and it would feel like two separate games stuck together. Similarly it would have been boring to just rehash the afore mentioned features from the Human half that weren’t in the Alien half (i.e. adding alien ammo dispensers). Though, it's not like other FPS introduces new features every visual theme change or episode; Wolf3D, Doom, Heretic etc don't.

Graphically, I think I screwed up on the flat choices for the converted maps (i.e. poor choices); something else I fixed in my version of the TC shortly after release. There isn't really much more I can say regarding the TC's graphics because 99.9% come from Corr7 and I've already mentioned the main weakness I believe there is in Corr7's graphics above. For a minor thing, I would state that Corr7's CD weapons are quite different in appearance to its Disk weapons and Capstone's artists decided to flip angles 2-4 to make 6-8 for allot of the bad guys.

Something else I would have liked to have toyed with, was ambient sounds; there are random noises on the converted alien maps in Corr7 (and Corr7TC), but I mean noises emanating from the countless computers on the Human maps for instance; problem is there are simply too many computers that would have probably overrun anybodies sound channels and would lead to lot's of cutting. It could enhance the difference between the Human and Alien stuff though; the noisy Human maps to the near silence of the Alien maps.

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Thanks for sharing your thoughts, Vermil. Was very interesting read. :) Indeed you made a very nice TC. Surpassing the original. Back in time i wanted to play Corridor 7, but i didnt have a computer to handle it. Then, when i had a Pentium, DooM eclipsed all those "Wolfstein-Clones", never wanted to play them.

Until now. Im still in the first half, but so far is very fun. I like the levels, yet simple and flats, im enjoying a lot!

So thank you. I hope you will improve with all stuff you said, to make it even better.

Now, if you could make the same with Zero Tolerance....

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Thank you for this great Corridor 7 TC.
I love this game a lot for its paranoid sci-fi spirit.
Tried playing original in dosbox, but for years got too used to mouselook and WASD. You did great job and even added more tense with such cool lighting effects.
I just turned off bilinear fuzz from console with "lowres" and now its just looking perfect to me.
Thanks again and good luck with new projects :)

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I'm still around; thanks for posting new links. I'm also very proud that my old TC is still getting any attention. Thank you.

These days. Dday has reached the point where it has the features to turn Corr7TC into a standard mod, as opposed to one that runs off a now ancient standalone version of Dday. However, Ddays various disabled features, due to the ongoing rewrite, since that time, would proceed to stop it working in modern Dday for the being. Also it turns out that what I thought was a variant of a Doom rendering hack I used extensively was actually a rendering hack specific to the rendering hack code used by Dday 1.8.x: Ddays rendering hack code has since been completely rewritten.

I did actually get most of the way through a v1.3 that would have featured the demo versions unique level and the original Level29, back in the day, but I never finished it, believing the TC had been played by all those who would be interested it by that point any way and, as mentioned, it was getting on a bit by that point.

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