I had grand plans to build a web-based, server-controlled MMO version of Super Puzzle Fighter.
I finished the product, but couldn't find a partner that had graphic design and marketing skills that wanted to help.
So, here's Puzzle Brawl. You can download and run it as a normal SBT project, or see it in action at https://puzzlebrawl.com
While I doubt anyone will get much use out of the game (though, try it out, it's fun).
It uses WebSockets to pass game information as fast as possible, using a shared Scala library that compiles to both Scala and JS. All the animations and tweening are handled by Phaser.
The entire app is a well-groomed project, and serves as a good "kitchen-sink" example Scala project.