Fun with Hardness Proofs: Candy Crush and friends are (NP-)Hard!
Channel: Koalemos
Date: 2015-01-28

Excerpt from Erik Demaine's lecture 6 of the "Algorithmic Lower Bounds: Fun with Hardness Proofs" course at MIT (Fall '14). 
The high level idea of a hardness proof for Candy Crush and other similar games is presented. 
Original video: http://courses.csail.mit.edu/6.890/fall14/lectures/L06.html.
Watch the full lecture videos here: http://courses.csail.mit.edu/6.890/fall14/lectures
The proof in this excerpt is playable at http://candycrush.isnphard.com.