Block Blast combines block-puzzle and brick-breaker elements. The player's goal is to earn as many points as possible by removing blocks repeatedly from cells on an 8x8 board that features a black, line grid against a dark gray background. They complete this task by transferring various polyomino shapes to the board to make rows and columns that feature eight blocks per line.
The game blasts away a completed line and transforms the blocks into square-shaped bubbles that match the color of the last polyomino shape used to complete the line. Once the bubbles fade away, the player repeats the process to create as many lines as possible until they run out of shapes that fit into the empty cells on the board.
Block Blast rewards the player with points displayed in white above the top center of the board. If the player removes more than one line at a time or single lines in a consecutive fashion, they win extra points for achieving combo moves. If the player runs out of moves, they can revive their game by watching an advertisement. If they don't watch an ad, they must attempt to beat their last-best score displayed in gold next to a crown at the top-left corner of the game area.