It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

×
Before buying I want to know if I can crossplay with someone who owns the steam version.

Also is it LAN online or does it force you to use the GOG account / client?
It doesn't appear possible. Steam seems to use Steamworks for multiplayer. GOG version seems to use IP.

When hosting from Steam, the joining GOG player can't connect to my IP. When hosting from GOG, the joining Steam player just gets a message saying "No friends are playing Grindea" with no option to enter an IP address.