I was messing around with WebRTC before I started this and I wanted to make a game with it. As far as I know, this was the first ever p2p WebRTC game ever made when it was first demoed in early 2015. I chose Phaser because it was an up-and-coming engine for the browser. I made browser games before, but with java applets. Phaser was easy to use and surprisingly performant. No regrets.