Please i play this game with my friend and we are so sad but no multiplayer no coop and please add multiplayer.
It may be kitschy but though it was
Multiplayer has been suggested before and talked about.
https://trello.com/c/kn6uUQhX/28-multiplayer
As well, The game is, basically just at the ground works and basics level of development - It's quite.. possibly a very long ways away from co-op implementation - And there's no telling how often multiplayer might shut down or break in updates afters its introduction. and afaik - the dev "team" is a rather limited number of people. It's not like there's a sub-group dedicated to networking and multiplayer, like some larger companies would likely have.