Big Bad Waffle just open sourced their game Isleward, a multiplayer roguelike game with the art of a classic 1980's dungeon crawler. The game is based around forming a party and exploring different islands, spelunking and completing dungeons in search of treasure, while strengthening your character through looting for better gear and leveling up.
From the original reddit post:
For the past year, I've spent a large chunk of my free time working on a multiplayer roguelike called 'Isleward'. 'Working on' seems wrong though. I've lived and breathed Isleward, along with a few dedicated fans in the discord channel. You guys know who you are!
Isleward is inspired by classic MUDs and roguelikes as well as newer MMOs, RPGs and ARPGs. Initially, I was planning on making it free to play (on a hosted server) but the more I worked on it, the more I realized that the project was simply too big for one person. I had too many features I wanted to build and too many maps I wished I could add for me to think it would be achievable in my lifetime.
So a few weeks ago I decided I would 'give' Isleward to the world. The code-base has been completely open-sourced (under a very permissible license). I've also started working on making modding easier (use the staging branch if you want access to these changes for now). My intention to continue working on the game hasn't changed; I'll still likely be the most active contributor to the project.
As the game is structured now, anyone can get the source and host a server that other people can connect to over the internet. You can download mods (only one has been written so far - by me to serve as an example) and add new maps. Mod support is still rather rudimentary but it's super easy to extend, which is something we'll be doing as the community grows.
Isleward is written in NodeJS (server) and JS (client) and I feel that the code-base is relatively neat and maintainable, if contributing is the kind of thing you see yourself doing. If you don't want to run your own server, you can always just find another server to play on (at the moment there are only one or two being run (one of them is being run on a Rasberry Pi 3) but that'll grow once people start messing around).
And that's basically it. Thanks for reading this far!