This one is a top contender! I had a buddy hop in with me to pull me away to play Deceive Inc. but the both of us ended up playing this to the win screen. That's a huge win in the fun book for something as mind bending as complex laser dynamics.
I think ultimately, digging in-and-of itself is a satisfying activity. Minecraft, Space Engineers, and all the clones in between are successful for it because the problems come naturally, and you really do think about how to solve them (life before stone-breaking was painful).
This is a likely candidate for top prize. Well done, sir! Well done, indeed!