Like the original (https://gabrielecirulli.github.io/2048/), "2^+" challenges you to get to 2048.
Here are the different tweaks:
1. "The Single Pringle" - gets rid of a single block
2. "The Groupie" - gets rid of blocks of the same number
3. "The Dynamite" - gets rid of all blocks except for the highest number
4. "The Multiplier" - multiplies the number by two
Enjoy!