Good stuff, my dad showed this to me as he was working on some home automation and now I'm using it to control the vent fan in my van. I love the ESP8266, it's such a fun little platform and it's very easy to find accessories for them. The little relay board I have was essentially plug and play.
I've definitely got my money's worth from this one, there are a lot of interesting emergent qualities in the game and the map has a lot of secrets scattered around it for you to discover. This game took up my evening for a few weeks when I first got it, so well worth the money in my book. I still come back to it from time to time as it's under pretty active development.
I really enjoyed testing the limits of the engine and using the wand system to craft interesting physics things.