XXI: 21 Puzzle Game is a brain-teasing game developed by TMSOFT, available on Android for free. The game consists of 200 unique and challenging puzzles that require the player to get a sum of 21 in every row and column. The player needs to move the gems around on the board until a solution is found. All gems have a unique numerical value, but the special gem that can be either a 1 or 11 adds an extra level of challenge to the game.

The game is designed to get harder as the player progresses through the levels, making it a challenging game that requires strategy and logic. XXI: 21 Puzzle Game is optimized for all Android phones and tablets, ensuring a smooth gaming experience. The game also features beautiful music, sounds, and graphics that add to the immersive gaming experience. Additionally, players can share solution photos with friends and compete for the highest level on the Google Play Leaderboard.