It's quite some time since i played the game 2048, but this implementation of the game is quite good. The planet graphics are nice. Like the clean look. Music is really relaxing.
You have written in the description that you made all graphics except the background. I don't know why you skipped on the background, because it doesn't really fit the art style of your planets and it looks pixelated. And by doing it by yourself you could have added some movement of the starts or shooting stars because the game is quite static and this would have given it a nicer look. Maybe consider this when going for your mobile build ;)
Another point is that some movements are not registrated. Some times when two planets should merge they are not merged. Only if I do the same move again. I can't provide any proof now, but I think when you play your game again you should have an eye on this ;)
I would really appreciate it, if you play and rate my game too. And a comment would be nice too ;)