So there's this one lost map from way back in Valve's involvement with the Team Fortress series, Lobotomy. It was meant to release with Valve's Team Fortress but neither it or the map ever came out, it had some Control Point-esque gamemode where both teams tried to destroy the other base's reactor, first by destroying the two security terminals locking them away from it. But also the team that held the base could repair those terminals to buy more time for their side to destroy the other sides reactor. (Its kind of hard for me to describe but I gave it a shot.) Using this one image I tried to recreate whats seen, for it I made a couple custom textures out of HL1 and HL2 textures and stared at the one screenshot for a while trying to get the textures to line up right, pretty proud of what I achieved. Also there isn't anything outside of what you see in the recreation currently, as we don't know what that looked like. But I will be going through and attempting to create areas that would fit with gamemode and map. I don't really know how successful I'll be. (Last two images are some of the custom textures made for this, just because I had more room to add images and felt like showing them)
Y'know its projects like this that make me realize I have no idea how you're actually meant to make a Multiplayer map, I've made one before but I never playtested it before release and got lucky that it wasnt totally awful. I'll definitely be trying to figure out how this kind of thing works for a while.