1212! is a casual, endless block puzzle game. The player must arrange block pieces on a 12x12 board that features a light taupe background and a dark taupe grid to create 12-block horizontal and vertical lines. When they make a line, the game removes it and rewards them with points. Their goal is to play for as long as possible to earn the highest score. If they run out of space on the grid, they must start over to beat their last score.
The game requires the player to arrange a set of three single blocks, polyomino shapes or a mix of these pieces on the grid before it provides additional another set. The player can create a single line or several partial lines and then use a final block or shape to finish the lines.
1212! forces the player to use flashing blocks and shapes to remove one or more blocks as well. For example, the player might receive a flashing three-block horizontal polyomino shape. They must use it to remove a single block or part or all of another shape. If they don't use it, no new sets will appear in the area to the right of the board.
The player can track their current score, pause the game, and check their last-best score in the upper-right area above the board.
