21 Black comes from Bit Free Games. The object is to score points by combining adjacent tiles to make 21. Two identical tiles never add when they merge. Two 6's will yield one 6.
  I've played the endless mode. This is an interesting game. The idea is great. The graphics are very good.

Where 21 Black falls short: if played perfectly, you'll never lose. You can even make a lot of mistakes and easily overcome them.  I stopped at 1000 points and then intentionally lost.

Another problem: the program does not always save your game mid stream.
https://itunes.apple.com/tr/app/21-black/id1044373988"mt=8

Other Point Scoring Games Worthy of Your Time (Some are no longer available.)
NumberMania
Four Straight Lines
Pushopolous
Stickets
Folt
Nineout Nineout II
BeeCells Lite
Kindly Colors
HexAgony
Domino Drop
Put Number
Tripevo
Triple Town
Kindly  Colors
COLORswipe
SubaraCity
Virus Pop Smash
+1 Number
4 Way Puzzle
Merged!
EnsoPolitaireTreplenumDanceBlack Boxeso:anquan
LevelsBucketsHit N RunPuppo!Omino!Super SwipesMake SquareColorzam
Color 6
Sticks.
Announcement:
The annual PAGY Awards are fast approaching. Each year, I nominate the best Puzzle App Games of the Year on December 30.  The winners will be named December 31.

Note: the PAGY Awards are very subjective. (Just like the Oscars, the Grammys and the Pulitzers.) The first purpose is to draw more people to the joy of puzzles. The second is to recognize the ind...