A game played by marking squares in a 3x3 grid. X goes first, and the first player to connect 3 squares in a row, column, or diagonal wins the game. If all squares are filled and neither player has won, the game ends in a tie.

See also: Wikipedia

Tic-Tac-Toe, except each square of the board contains an inner game of Tic-Tac-Toe.

Players start in the middle square, and their move in the inner Tic-Tac-Toe board determines the square the next player must move in: eg. if X takes the top right square of the middle board, O must now make a move in the top right Tic-Tac-Toe board.

When a player wins an inner Tic-Tac-Toe game, they take the corresponding square on the outer board. If a player is sent to a won or drawn square, they may instead move anywhere on the board. Winning the outer board wins the game.

See also: Wikipedia

[...]

Inspired by pokemonchess.com.

Pokemon chess is like chess, except at the start of the game each player secretly assigns each piece a unique Pokemon type. When a piece attempts to capture another piece, the following happens based on the type matchup between the two pieces:

• If the capturing piece is normally effective against the piece being captured, the piece is taken like in regular chess.
• If the capturing piece is super effective against the piece being captured, the capturing piece gets to make an extra move after this one.
• If the capturing piece is not very effective against the piece being captured, both pieces are captured instead.
• If the capturing piece has no effect against the piece being captured, nothing happens and your turn ends.

There is no concept of check in Pokemon chess, as the king may be immune to certain pieces depending on their type¹. Instead, the game is won by capturing the opponent's king.

For additional fun, a capture has a 1/10 chance to become a "miss" or a 1/16 chance to become a "critical hit". If the capture is a miss, the move has no effect regardless of type matchups (nothing happens, and the turn is over). If the capture is a critical hit, the move is super effective regardless of type matchups (the capturing piece may make an extra move after this one).

¹ Consequently, the king is not prevented from castling through, into, or out of check.

See also: Reddit post explaining Pokemon chess