The worldspawn seems to be correct, and I've been using TrenchBroom itself for compiling.

https://imgur.com/a/tEAKYRC
Here's the parameters, I wouldn't be too surprised if something's off there. 

Okay, it seems to have started working once I moved the .map file to the base folder that I'm using, rather than in id1/maps 

Hey guys, just "finished" my first multiplayer map for Quake 1 and thought I'd post it here for some feedback.

Had a couple questions:
1. How do define my map as a multiplayer map? Its loading as single player map despite me placing multiple deathmatch start entities in the map.

2. How do I get my map to show up in the multiplayer map selector on Quake Remastered?

Map: https://www.dropbox.com/s/hpx1evwrd7oiqty/ReignBeta.zip?dl=0

Screenshots 1: https://www.dropbox.com/s/mjth3xz5tug71ha/20210904214013_1.jpg?dl=0

Screenshot 2: https://www.dropbox.com/s/4zklg6z8n3k1tr8/20210904214022_1.jpg?dl=0

Screenshot 3: https://www.dropbox.com/s/iqgiltdyub7ewk1/20210904214135_1.jpg?dl=0

Screenshot 4: https://www.dropbox.com/s/btjimdjamnyveme/20210904214239_1.jpg?dl=0

Screenshot 5: https://www.dropbox.com/s/35uz08p650g94ds/20210904214252_1.jpg?dl=0

Screenshot 6: https://www.dropbox.com/s/om0of4bexprs9mr/20210904214311_1.jpg?dl=0 

#1 - You must be in multiplayer/deathmatch mode. Can do this by setting "deathmatch 1" ( or 2, 3, 4, see https://quakewiki.org/wiki/deathmatch ) and then loading your map. If you start multiplayer game through the menu, that's what the game basically does, setting deathmatch no non-zero (or coop 1 for cooperative play).

#2 - Maps showing in the level select menu I think are configured in a special file you can find in \Steam\steamapps\common\Quake\rerelease\id1\pak0.pak\mapdb.json though I don't know if editing it is a good idea. In case you want to experiment, don't put the edited mapdb.json back into pak0.pak (although you can always verify installation in Steam and redownload 'wrong' files), but rather pack it into pak2.pak file 

Did you happen to add bot waypoints to this map? If not you might consider it. I haven't tried this but eventually I hope to do a tutorial on it.

https://steamcommunity.com/sharedfiles/filedetails/?id=2580864534 

Is there a hacky way (in vanilla or copper) to make a timed power-up (Quad, Biosuit etc.) last for the duration of the map after picking it up? 

Probably not - the code for powerups doesn't leave many loopholes. to set powerup state on a player, the code requires an entity with the classname of the actual powerup to touch that player. Only thing I could possibly see working is some kind of trick that teleports a powerup onto the player every 30 seconds, but not clear how to hit that moving target.

As an alternative, consider repeatedly respawning the powerup (using a simple hack), so the player can have the effect continuously, if only they go to pick it up every time. 

Ah-well, thanks anyway Preach. Back to the drawing board! 

I've got a setup in a map (for copper mod), whereby the player has to hit three buttons within a short timeframe in order to open a door that also only remains open for a limited amount of time. If the player doesn't make it through the door in time, they have to hit the three buttons again.

I've got a little black room outside the playable area with three doors (each with a wait of 5), a shooter and a shootable button. Each of the three buttons in the playable area target a trigger_relay. Each of these relays fires the spike shooter and opens one of the doors in the black room. Once all three doors are open at the same time, the shooter will be able to hit the shootable button, which targets the door in the playable area.

So far so functional, but I wanted to display a nice "2 buttons remaining" sort of message as is standard practice, so I also pointed all of the relays to a trigger_counter flagged to repeat. The problem is, the counter won't reset if the player does not complete the sequence in the limited time given them, so if they have another go without completing the three counts, the count goes out of sync.

I hope my description makes sense, because I hope somebody knows how I can fix this or rebuild it more effectively!

Thanks. 

You could instead have some physical representation of "button presses remaining" visible in the map, controlled by your logic (e.g. glowing rune plaques that change/disappear) ... it's not as clear of a message, but on the other hand some folks might even be happier with that sort of thing than with a centerprint. 

That's a really good idea and could also nicely convey the connection between the buttons and the door! 

Bit of self-promotion here: These map hacks should enable you to put the centerprint messages into your map. You really want to use the hack from the second article, but give the first article a skim because the second one builds on it.

https://tomeofpreach.wordpress.com/2016/02/21/reusable-trigger_counter/
https://tomeofpreach.wordpress.com/2016/02/23/more-reusable-trigger_counter/ 

thanks Preach! 

Does anyone know if there is a way to mirror a model (mdl)? I have a weaponframe of a hand with a hammer, but it is left handed. I need a way to mirror all frames so they become right handed. 

You can do that in QME.

Open the model. Change into Object tools editing mode, and make sure that "root" is selected by clicking in an empty space. Change the settings at the bottom to:

Scope All Frames
Model Relative
Subject Object

Type -1 into the Y box of the Scale control and press enter. Your model will be mirrored, but the triangles will be backwards. Change to Triangle tool editing mode, select all the triangles, then right click and select Flip Triangles. Now the model should be mirrored as desired. 

Thanks Preach!
I guess I learned something new with this program again. Saved me a lot of work.