Double Dooming! Is this gameplay possible?

[remembert]

Originally I wanted to do this just to make a demo file that could beat e1m1 and map01 (see demo forum) but now I think this would be incredible amounts of fun! Here's my idea:

I want to have two Doom games running simultaneously, and have my keyboard and mouse input work for both games. With two different levels loaded, a wholly new sort of gameplay would arise, where you have to keep two parallel doomguys alive in two separate levels while they share all their actions in common. This would create a challenge and a new dimension of play for even the tired old levels of e1m1 and map01 (played together of course) while harder levels would be a huge challenge but still fun to try. Some interesting concerns would be:
-How to navigate different levels when your doomguys face the same direction
-How to have different weapons drawn in the two games
-Ammo conservation (You don't necessarily want one game always shooting into empty space)
-Finishing both levels at the same time
-Keeping both guys alive!

Unfortunately I only have one monitor, so a split-screen view would be necessary (though I could scrounge up another monitor if absolutely necessary). Being able to make a demo file that beats both levels would be icing on the cake, but the actual gameplay is much more important. Is there any way that I could set this up? If not, I hope I've sparked someone's interest out there. I'd love to see this idea implemented in a port or another project.

[Maes]

Quick answer: not in the general case of any two levels. There are far too many differences in level layout, ammo, monsters, and traps/dangers.

Not-so-quick answer: it could be done by using some cheap tricks, and relaxing on some conditions

For example, start both levels, but move so that the player in one of them gets "stuck" in a place that's hard to exit without precise manoeuvres (e.g. lock him inside a small safe room). Then, being sure that the trapped player cannot exit that room, be attacked or fire a rocket , finish the level "normally" with the other one. Once you do that, focus on the "stuck" player. Sure, this way relies on being able to "safely park" one of the doomguys, and doesn't allow for simultanous level ending.

It could also be done if Tool Assisted, on levels with -nomonsters, or even with monsters but relying on precise RNG prediction and previous knowledge of exact monster movements and behaviour, and planning movements ahead so advancing in one game produces a safe backtracking or even no difference in the other game (e.g. walking towards wall, avoiding falling into pits, avoiding RNG-predicted monster attacks, etc.)

Even that way, there will still be levels couples which have no "common solution" or will be too long and tedious to combine, as most of the time you'll advance in once while idling on the other, even with the help of speedrunning tools, and ofc it's not properly applicable to levels with too different lengths, although it's possible to deliberately "delay" the shorter one while advancing in the longer one, again with carefully planned TAS-generated movements and input.

In other words, "multidooming" would probably be possible only by if tool assisted, carefully manipulated, pre-planned and mostly automated/scripted, and near-impossible to do in real time by a human player for any two levels, except by using the cheap "parking" trick and not needing to finish EXACTLY (or even nearly) at the same time.

[Soap on a Rope]

I've seen a run like this where the person did Megaman X and Megaman X2 at once. It was tool-assisted, of course, but it was pretty cool to watch.

I imagine a Doom/Doom 2 one would be much harder to make, but I'd definitely watch it.

Here are a few things I could see being problems:

-Ammo. Every shot you fire on one screen is fired on the other screen. For example, taking out that cyberdemon in E2M8 with rockets is going to mess up the Doom 2 side's ammo supply big time - you might want to make sure Doom 2 is using a fist/chainsaw/pistol at that time.

-Weapons. This was pointed out already, but it's a big issue. Perhaps you could make use of the forced weapon switch when you pick up a new weapon or when you use up all of the ammo on a weapon.

-Demons. They move fast and often come in swarms. It could be very tough to maneuver around them!

But yeah. It would be difficult, but it's probably possible. Anything is possible! *looks up, watches a purple butt fly out of a black hole*

If you ever make progress, even if it's just the first level of each game, please post it!

[Maes]

As I said before, such a "demo" would probably have to be TAS generated, ideally coded by hand tick-by-tick, e.g. by observing object movements for both levels on a 2D map, and choosing at each tick, the more appropriate movement that works for both tables.

In other words, it would have to be constructed step-by-step, and we're not even discussing of achieving UV-max on both, as this depends on the number of monsters and different ammo and weapons available on each level.

A sort of "finish ASAP" speedrun that should be fun to watch could be possible for some carefully chosen levels, but for any two levels most of the movements will consist in boring, continious micro-backtracking and micro-strafing in order to keep the doomguy alive, correct doomguy's course etc. And yeah, firing will probably be nonsensical or useless in one of the two screens , except if you exploit RNG predictability to the max and fire ONLY when you can hit a target in both...

Whatever that is, it can't be considered as "gameplay". Sure, you could also make a sort of TAS-bot that circle-strafes a cyberdemon or any monster at point blank and finishes with the chainsaw/fist without taking a hit, but since it's not HUMANLY possible it can't be classified as "gameplay".

[remembert]

Well, I was already aware of all these difficulties for the actual playing, and I'm not particularly interested in making a demo. I'd lose any remote interest in making a tool-assisted or constructed demo before I even learned how to use the tools. I really just wanted to try this for my own fun on some very simple levels, and take it from there.

So, to rephrase my question: Is there any way I could control two Doom programs at the same time? I mean this in a technical way, I'm not referring to the difficulties of actually playing the game. I imagine this is a question to take to more tech-savvy forum, as Windows itself might not allow this to work.

Still, thanks for your input! And yes, this is partly inspired by that Megaman X/X2 demo.

[Maes]

remembert said:

So, to rephrase my question: Is there any way I could control two Doom programs at the same time? I mean this in a technical way, I'm not referring to the difficulties of actually playing the game. I imagine this is a question to take to more tech-savvy forum, as Windows itself might not allow this to work.

I doubt two windows programs would ever work with the same keyboard input. You could try setting one to use a joypad for control and play with 4 hands ;-)

Or build some keyboard/mouse splitting device and use it on two computers at the same time :-D (There MAY be the software equivalent of this, which allows multiple keyboard/mouse emulation).

Recording a "double demo" is however of entirely different technical nature, as it would require starting both Doom's at the same time in demo recording mode, and they would need to be perfectly tick- and RNG-synchronized throughout the whole ordeal.

The resulting lmp files, IN THEORY, should be equal byte-per-byte for both Dooms and work the same no matter where you play them, and should show a demo capable of finishing both different levels, as they only record player movements per tick. Needless to say, you'd need a special version of doom to accept/share input between multiple instances, synchronize multiple instances timers/RNGs and allowing tick-per-tick TAS gameplay.

IMHO, all this is too hardcore even for the most extreme nightmare tyson 100% speedrunner :-)

[Technician]

I would set it up to have two maps with two joysticks. One for your left hand and one for the right. All keys like fire and open will of course be on the joystick so you would not have to remove your hands. This would be awesome. I'd be like a piano in Doom. Laft hand would be the bass clef and the right your treble clef. It would be very similar because you have to read two forms of information and act simultaneously like in piano.

I would love to see this done.

[Vegeta]

The closer you can get atm I think is using Legacy. With DB put to levels in a single map, two player starts, and play splited screen co-op. If you want the maps to be from DOOM 1 and 2, use Enjay's DOOM 1 texture patch for DOOM 2 (allows to play DOOM maps in DOOM 2).
Another chance should be to play this kind of co-op in normal maps, using only one hand with each player. It'd be harder to move, yet with two marines and the unlimited "lives" the map could be finished.

Now for the first poster, set the same keyboard for the two players (if Legacy allow this) and voila.

[remembert]

Thanks for the input. As I think about this idea, it seems crazier and harder. Still, I think it would be an interesting idea for a single project, where you play two linear levels with the same layout but slightly different monster set up.

I should stop changing the subject.