We’ve been working part-time on our own take on the IO game for close to a year. Exocraft is an action/strategy persistent MMO that is focused around more depth and progression than most IO games. You start as a small mining vessel and build up your unique ship using dozens of available parts. Team up with others to mine and battle planetary defenses on a dying alien world for resources, or compete in skirmish-style tournaments to reach the top.
The game is built with Phaser-CE on the client and uses a custom server built with Node.js, MongoDB and Redis -- backed by our own GoldFire platform for signup/login, communication, achievements, etc. All players are in the same world, so there are no servers to choose from. As more players come online, the world will dynamically size up and down to fit the number of players and maintain resource balance.
You can play now at https://exocraft.io, and any feedback is greatly appreciated!