Defold: Free 2D Game Engine for Cross-Platform Publishing

A tech lead from King wrote a game in Defold and streamed on livecoding.tv: https://www.livecoding.tv/video/small-game-from-scratch-part...

So, a 2D Lua Game Engine with a Scene Editor?

At a cursory glance it seems like https://coronalabs.com/, but it's free, which is nice :).