What are some alternatives?
When comparing Betract and XOLT, you can also consider the following products
2048 Alphabet - Version of the 2048 game - 2048 Alphabet wiht letters,
2048 - Puzzle game written by 19 - year old Italian designer Gabriele Chirulli based on 1024.
Digit Disorder - Digit Disorder is an easy to play but hard to master video game that is specially made for math lovers.
2048 by Uberspot - Port of the 2048 game by Gabriele Cirulli. It's playable without network connection.
Fives - Fives is a Quite Challenging Puzzle video game by Higher Bar LLC.
Threes - Threes is an Amazing Challenging Puzzle video game developed and published by Sirvo LLC.