On the surface, 21 consists of two players battling in a series of head-to-head blackjack games.
Each player starts the game with 10 health points and 1 attack power. At the start of each round, each player is dealt two cards (1 face up, 1 face down) from their own deck of 11 number cards, consisting of 1 each from 1 to 11.
On each turn, a player can choose to either:
- Hit: Draw another number card face-up from their deck (up to a maximum of 5 cards on the table), or
- Stand: Pass the turn to their opponent.
Once both players have stood in succession, the face-down cards are revealed, and the winner of the round is determined as follows:
- If exactly one player's total goes over the target score of 21 (a bust), they lose and their opponent wins the round;
- Otherwise, the person with the closer total to 21 wins the round.
- If both player ends up with the same total, the round ends in a draw with no winner.
The winner of each round deals an amount of damage, equal to their attack strength, to their opponent. The person who reduces their opponent's health to 0 wins.
So far so good, right? Well, introducing...
At the start of each round, players are dealt 3 spell cards that can change the game in various ways (e.g. change their attack strength, draw a specific number card, change the target score,...). They can hold up to 7 spell cards and can play any number of them on each turn before choosing to hit or stand.
We believe spell cards will add more layers of strategy to the classic game of blackjack, and is guaranteed to create some chaotic fun!