UE4 videogame based on paper board games I used to play as a kid. It is multiplayer through IP connections like Minecraft. It works over LAN and can work over the internet either through port forwarding or direct-linking P2P VPNs like Hamachi/Wippien (or maybe somebody would be so kind as to set up a matchmaking server for UDP hole punching? :p). It also works for local play if you load up the game twice and enter localhost or 127.0.0.1 as the IP. Source-engine-like server list may come soon using Epic Online Services if UE4 decides to support IPv6 or adds an EOS online subsystem (or if I can get UPnP working with my finicky router, but that is doubtful).
This project has nothing to do with Paper2D. It's just called paper because of the paper games mentioned earlier.
Grab the latest build: https://github.com/goodtrailer/Paper/releases/latest
For a full list of releases: https://github.com/goodtrailer/Paper/releases
Or get MVPTBS, a two-year-old Unity game that is the predecessor to Paper: https://github.com/goodtrailer/Paper/releases/tag/unrelated
Load PNGs from disk that follow the map-making palette below.