Hey I am very interested in trying this project out! The only question I would have before I get into it would be if its possible to just make a 2v2 PvP game that I could play with friends locally?

Sort of like both players choose two characters, get items from a shop with a set amount of currency that they'd have and then head into the PvP battle?

It doesn't have to be controlled by two different controllers or anything like that, the same keyboard would be perfectly fine.

While I'm sure there's stuff I haven't thought of, I imagine this wouldn't be too difficult to do with this setup. You'd want to change the victory conditions, make a new type of player unit that faces the other way etc, but you can make most of what you need through duplicating the player one stuff and making minor adjustments.

even on one controller you'd want to know which player was which to determine who wins, who the default target for offensive/defensive abilities should be, what side to stand on, etc etc. So that doesn't make things any easier per se but either way it wouldn't be too difficult to implement with some basic GML skills.