Alright, time for my most insightful and least useful post so far! The promised Sandy Petersen Doors analysis.
Basically, you guys missed the fact that Sandy doors aren't true doors in the sense all the other id mappers understood them. A door is a construct that has two sides, right? When you look at maps by Romero, McGee, Hall or Green, you see the vast majority of their doors having mirrored actions. I'll go as far as guessing that DoomEd had a tool that did this for you when you used it on a sector. And either no one told Sandy, or he (partially?) chose to ignore this feature.
Sandy doors are fairly abstract constructs that only work as much as the map layout requires them to. They're NOT arbitrarily mirrored! With Romero or Hall you can often see "pointless" symmetry on stuff like secret closets acting like a DR door from both sides, or even utterly redundant symmetric D1 on keylocked doors. Sandy would have none of that, such a closet would be D1 and the other side would have no action at all. Actions get assigned only if there's a chance they'd get used, which leads me to think Sandy wasn't using some door feature and pondered upon actual functionality of every door he built. That's quite weird when you realize he was the "flood mapper" spamming out speedmaps to fill the quota, heh.
Enough preface. What is a sandy door? Your typical Sandy door is a symmetric DR door with action 1 (open wait close, monsters too). This is what connects all the usual rooms and interestingly enough, Sandy's doors make it easier for monsters to travel around the map. We often connect this feature to Romero, but with him it's the layout, the mild verticality that lets monsters roam. His doors are quite the roadblock as he ignores action 1 for others like action 117 (DR fast), 118 (D1 stay, fast) or 31 (D1 stay). If it's a common door, Sandy simply lets monsters use it as well. Shame the original Doom engine bugs out and makes it so hard for them to walk under door sectors, heh.
Then there are keylocked doors. These are almost always symmetric for the other mappers and almost always one-sided D1 for Sandy. Got a key? Well, you open the door and it stays. The other side? Why would I care about that? Yep, Sandy only assigns functionality to the other side if the map requires it. If there's no way for you to appear on the other side, then you don't need the door to work from there. Proofs of that are strewn over all his maps... and the special cases confirm it. Look at map08 PG/caco room - symmetric D1 stay. Why? Well, there's a DM spawn in the room! Look at map10 - this is actually a proof that Sandy totally reworked the functionality of the map (so it wasn't just a texture/populating job). All the doors are trademark Petersen, not Hall. The keyed doors are either D1 key-only from one side, or they have assymetric behaviour from the other side, depending on what Sandy needed. The D1 BK door leading to the cyb room is DR action 1 from the other side (and as it happens, you can get to that room by a shortcut). The exit room two-door sequence has the first flagged DR YK open-wait-close AND DR action 1 from the other side, while the second is D1 BK stay. Even if the functionality is kinda random, the "control" of it is very consistent. This is why the famous map27 trick happened - the exit door is DR RK open-wait-close, but it's DR action 1 from the other side, because who knows, maybe the player wants to explore the map before exiting. And the door is thin enough for the archvile bug. Looks random, but it's actually following Sandy's modus operandi very tightly.
There are exceptions though. Of course, Sandy being the trapmaster, a lot of his doors are completely function-driven, so some maps/rooms will see a lot of close-door linedefs, SR actions, etc... but those are even less of a "door", heh. Then there are exceptions coming out of rushing the job, or at least I think that's what happened. map10 can trap you in the exit room, because it has DR a1 just on the outside (which means it's a half-assed Sandy door). map01 has a symmetric DR a1 door for the secret imp closet instead of one-way D1 - I assume it's meant to be a hideout closet for DM, heh. map12 has a freak accident in the exit room where the outside is DR YK o-w-c and the inside is D1 RK stay. Oopsie! map09 has a rare occasion - the exit area (not the exit room itself) are symmetric DR YK o-w-c! I assume it has something to do with the DM spawn inside the room, even though I'd expect DR a1 at the inside. There's a symmetric D1 BK stay in map24 that probably can be explained by DM spawns as well. Then there's map24 and the double door before the exit door. I have no idea what that's supposed to mean, it's totally superfluous, nonsensical and basically looks like a pointless experiment. :)
So, what does this insanity mean for d2twid? I'll go through all the Sandy-inspired maps, using the e8 public release.
map01: Clean job, good call on the S1 when exiting the BFG area. The secret chainsaw area doublesided SR is so-so, but not unheard of (map12 and map19 have at least one of those).
map07: All doors are perfectly one-sided, heh.
map08: S. 105 (leading to exit area) should be D1 RK stay from the outside, action 1 from the inside (no worries about monster opening it, the door is FAR too thick and there's no sound tunnel to the inside). S. 134 is correctly marked D1 from both sides because of the DM spawn, but s. 80 and 131 should be action 1 from the inside unless you want to call that the map09 exit area case. No worries about thickness either, the doom2 map27 door is 8 units thick while these are 16 units, making them impenetrable for monsters. S. 115 is nicely onesided trap door and everything else is proper Sandy action 1 mirror door.
map09: Good job using D1 on secret closets. Key-locked doors are symmetric though... minding that this is "Tricks n' Traps", the one out of the exit area should be action 1 (16u, safe), the one out of the big lift puzzle could as well be no-action and there can be a S1 open stay or a totally whack W1 open stay... or whatever, even action 1 would do. Just not a symmetric door, haha.
map10: Make both the keyed doors at the exit D1 open stay from the outside and you're set. No functionality needed from the inside. (You actually lock the player in the exit room, cause the inner linedef is flipped, haha. Might keep that as "leave it in".)
map12: S. 45 is symmetric action 1, but it's not justified... go for onesided D1. S. 106 has DM spawns on the inside, so it should either be D1 RK stay and D1 open stay from the inside, or DR RK o-w-c and D1 a1 from the inside (no monster can open it). Make s. 18 D1 BK open stay, the inside should be no-action. Action 1 on the inside COULD trigger monster opening, but since there's no need for an action at all... just keep the door open?
map13: All the proper doors are symmetric a1 (even though some have no monsters on the inside, but technically some could get in)... so that's very much fine. Except s. 147 being symmetric o-w-c fast. That's a Romero tool Petersen never used afaik. It p much calls for a D1 assymeric action there with nothing on the inside.
map15: S. 175 calls for a D1 YK open stay on the outside (l. 1021) and no action on the inside. There's nothing to justify the symmetry. Same thing with s. 186, except I'd go with DR BK o-w-c on the outside and no action on the inside. The room traps you inside anyways, so the door doesn't need an action there. Both exit rooms should be D1 RK open stay from the outside with no action on the inside. The remaining non-switch door is a proper symmetric a1. :)
map16: S. 92 is absolutely a D1 BK stay from the outside, no action from the inside. Same deal with s. 223 except that's RK. Same deal with s. 7 and YK unless you want to do something special with that. There's no DM spawn on the inside and no monsters to abuse it, so p much no action on the inside as well. The regular doors are proper symmetric a1s.
map18: I kinda think s. 71 and s. 95 (both early secrets) should be either S1 or D1 open-stay from the outside with no action on the inside as you can't happen to materialize on the inside. That or SR/DR and trap the player in, lol. No mercy. S. 7 is totally a no action on the inside (instead of BK o-w-s), I don't care if you want to close the door or not. S. 161 should have action 1 from the inside (no worries about monsters, door is thick enough). The rest of your SR doors are probably okay, although Sandy didn't use them that much (like, s.52 doesn't really need it... it could go with D1 and no action on the other side, heh).
map19: Action 117 on s. 101 alert. Calls for a1 instead. S. 19 should be DR a1 from the inside, I don't think it can be abused (thick, no sound exploits). S. 120 is a proper D1 RK open stay, BRAVO! There's even a one-sided DR a1 door at one place, hah. The rest is symmetric a1. This map gets closer to the original than most!
map21 (late marcaek edit): Everything in the map is a proper symmetric a1 door and the exit door is one-sided open stay, gj! If you want to go the extra mile, edit the exit bars to have action only from the outside part, not all around... haha. Yeah, id was lazy to put actions on all the sides.
map24: D1 open stay at exit, marvelous! S. 65, however, should be no action (trap the player in) or DR a1 from the inside (no DM spawn tho, so that's optional). S. 125 should be D1 BK stay from the outside, no action from the inside, imo. That's all, I think.
map25: Pretty good usage of D1 keylocked assymetric doors. A. 123 on s. 34 is questionable, but I dunno, it feels right there. As do the onesided SR actions in the southeastern maze. So all's fine, I guess.
map27: S. 120 has no right to have an action from the inside. S. 125... maybe (although technically, it should be a DR a1 one from the inside), but you could still go with no action and have the DM spawn exit the room via the teleporter until it's opened from the outside. Actually DR a1 could lead to something silly, like using a vile jump at s. 100, firing a rocket at the BK room, waking something up and using it to open the RK door... haha. Well, it's up to you. The rest is trapdoorish or symmetric a1 enough.
map28: The northern room is sound-proof, so s. 217 could be YK D1 from the outside and DR a1 from the inside (so the DM spawn can get out). Same with s. 68. Sector 101 shouldn't be YK D1 from the inside, but you can't use no-action because of the DM spawn that can go there... AND a revenant tends to wander there as well, so a1 would be risky as well. D1 open stay on the inside seems safe though. The rest is glorious symmetric a1.
map30: A. 117 on s. 53 and 41? Tssk. Where's a1?!
map31: All three keylocked doors should be D1 open stay from the outside only, no action on the inside.
And this should be all from me. I'd call this the most OCD post I've ever done, but I've done far worse with hoveritem hunting. Well, it's not like you HAVE TO implement these changes, but you wanted to go for total faithfulness, so here you go - Sandy doors!