21 Smash is a free and fast-paced card game developed by Norri Stockholm, available on Android. It's a game that combines Solitaire and Blackjack with the objective of getting 21s or stacking up five cards to smash them away. The game is designed for single-player mode and the player has to fight against the clock to finish as fast as possible.

The game has an intuitive interface and is easy to play. It's a great exercise for the brain as it requires quick decision-making and strategy. The game is highly addictive and players can compete with each other to get their names on the world ladder. Overall, 21 Smash is a fun and challenging game that is perfect for players who enjoy card games and want to test their skills in a fast-paced environment.