Multiplayer First or Later

I was wondering if it is preferred or even standard to make the game multiplayer first, or to build all the core concepts and then to move over to multiplayer. I’m getting frustrated with the multiplayer in my game, I plan on having a system such as Rust with redistributable servers that i can run officially but also for other players to be able to set up their own. I’m not sure the networking solution i need or if i should do it now before i start with the core concepts of the game or later.

It’s definitely something that could be done later (not at the start), but you need to think about everything you’re doing and how it could work in multiplayer. If you need to go back and change pretty much everything because you didn’t plan everything out well enough, then you’d have a problem. Doing it from the beginning will help that not happen.