You can now play local co-op multiplayer in Kitty Combat! You can also play it online with Steam Remote Play!
Now hear me out, I know remote play isn't everyone's favorite thing. However, at the moment with Gdevelop this is kinda my best option since it'll be the easiest to work with and cause the least lag and desync.
In this update when you press multiplayer on the Main Menu it'll take you to the Cat Island and there will be a new lil cat named PJ. This will be player 2, who can be controlled with the arrow keys. At this point you can activate remote play and share your keyboard with another person to play together!
As of right now you share health and when player 1 levels up, player 2 will get a scaling set of stat ups.
Keep in mind this is an early access version of multiplayer and it will likely have some bugs or issues that have plans to be fixed in the future.