Games similar to 6561 include 2048, which is free and open source. Other options are Sudoku & Variants, Suika Game, 2048 by Uberspot and Threes!. There's no shortage of Puzzle Games like 6561, with more than 50 alternatives for Android, iPhone, iPad, the web and Windows.
Kitty Cat Squash is a super-casual tile merge game! Use your paws to slide the cats across the board and merge the cat tiles; when merged, a new cat appears. You will get hooked attempting to beat your highscore, and trying to discover all 16 cats!.
3D version of 2048. 4x4 field with a second layer (playable at 2 sides). Changeable tile styles. Music and environment graphics.
Neves - merging puzzle game. Swipe to move all tiles. When two tiles with the same color and number touch, they merge into one higher tile. "N" is the final tile, if these two connect, they will be completely removed.
