Multiplayer in Bethesda's Elder Scrolls and Fallout games have always been a much-requested feature from some members of the gaming community. Due to the buggy Gamebryo engine and the structure of the games, multiplayer was never on the table. However, modders have taken it upon themselves to finish what Bethesda never started.
Game Informer did a write-up on an upcoming mod that's currently taking beta registrations called New Vegas: Multiplayer. It's a made-from-scratch multiplayer mod for Obsidian Entertainment's Fallout: New Vegas.
According to the Reddit thread from nvmp_corporal, the team is looking for beta testers to test out the mod for a debugging and quality of software exercise. They're also looking for more network programmers and reverse engineers who can help expand and stabilize the software.
They have a test video up of the progress they have so far, which shows some characters in an instanced room where they are demonstrating player synching, NPC data and AI synchronicity. It's as buggy as you would expect. Check it out below.
While it may be buggy, it shows a lot of promise. It's still early on and the biggest challenge is making sure that the data is stable across the runtime environment of each player.
On the upside, we didn't see any glitching through the floor or weird gravity defects, or items and clothes clipping. So the important aspects of the multiplayer beta appear to be worked out.
In a way, you can see with how janky the multiplayer mod is why Bethesda has steered clear of adding it in Fallout or their story-oriented Elder Scrolls games. That's not to mention that even as single-player games, there are still tons of glitches and bugs that modders end up fixing post-release, especially with Skyrim and Fallout 3.
In this case, modders are potentially opening the door for a Fallout 4 multiplayer mod if they can get the New Vegas mod to work right.
It reminds me of the early goings of the Just Cause 2 multiplayer mod, which seemingly came out of no where, but eventually went on to become one of the biggest draws for the game. Of course, the big difference between Just Cause and Fallout is that one is made to goof around in with wacky, over-the-top stunts and action while the other is more story-oriented with quests and a lot of world-building. So translating proper multiplayer into Fallout requires a lot more finesse than just making sure a hundred people can grapple onto a plane or 50 people can drive limos around a cliff side.
According to Game Informer, it will be possible to partake in quests with other players but it's still pretty buggy right now and killing the wrong NPC will fail the game for everyone. I can only imagine what would happen if a player unintentionally died before saving the game. In fact, how do save games even work in multiplayer? I guess we'll find out soon enough.
You can register for the beta over on the official website.