For those who haven't heard of Threes, I highly recommend giving it a try. It's the original game that 1024, 2048 etc were cloned from (and I think it's still the best by far). Wikipedia has a good summary: https://en.wikipedia.org/wiki/Threes#Legacy
I don't understand the peeve people have about mentioning Threes all the time. Does every discussion about a FPS game need to point out it's the same concept as Doom or Quake or whatever? The vitriol in some of the comments here are quite weird to me. It's also dishonest to label 2048 as a clone. Personally I never cared much for Threes, and same I guess with my parents etc which all got hooked for a while on 2048. 2…
Well the great differentiator between puzzle games is the idea of the playing mechanism. The great differentiator between FPS is implementation. If I make an FPS, I didn’t really steal from Doom because the idea is pretty obvious. But if I make a sliding game that’s very similar to 2048, you might say I stole the idea. It’s like with patents, subjectively the mechanism of a FPS shouldn’t be patentable to me, but three or 2048 might be.