So me and two friends attended the Global Game Jam over the weekend! It was a bonding experience, if not a bit stressful.
Now Phaser is okay, don't get me wrong. But we encountered some massive hurdles while working on it. It's a community maintained project, but the community for it is fairly small so really its a framework one guy has produced. We encountered errors that existed in later versions but not in prior versions and this caused us massive headaches at every step of the way.
Half way through we were fairly sleep deprived and because of these issues we ended up second guessing ourselves over and over again. We'd built a little template project before we set off for the jam, which turned out to screw us over when it came to calculating angles in a responsive canvas.
The game we made was related to a smart home, something like a smart Home Alone. We called it SafeHouse in the end and you can find the code to run it here.
In future, we decided that regardless of how little knowledge we have of Unity we'd use it. It's supported better and hasn't got silly bugs (and the ones it does are usually well documented).