My wife and I tried playing this evening and were never able to get more than 2 or 3 minutes into a game before whoever was the guest would get disconnected. I tried opening the ports on the firewall and disabling the firewall altogether on both machines. I tried playing over the LAN and hosting the game thru the "Game Lobby" instead of going direct peer to peer over the LAN (With the STUN option enabled). I tried both the version that ships from the Debian repo and the AppImage. I tried disabling WiFi on both machines and tethering our phones to use those instead of our built-in WiFi cards on both machines. Without fail, within 5 minutes at most whoever was the guest would get disconnected. If I was hosting, she would get disconnected. If we switched around and she hosted, I would get disconnected.
I understand that the game is alpha and there's gonna be bugs, but I see people playing so I'm assuming that this issue is unique to us or else nobody would be playing online, so I would like to get to the bottom of it.
Also, just to verify our router wasn't introducing some latency or that there were issues with our internet, I ran a few speed tests over the WiFi, since we're using WiFi to play, and this is about what my WiFi averaged in terms of speed and latency.