Tetris Blast

Tetris Blast is the North American version of Bombliss, a Tetris variant introduced in Tetris 2 + Bombliss. It features many unique Tetris modes mainly dealing with clearing the screen of all blocks by using bombs which were both given at the start as well as in the tetrominoes. In addition to the tetrominoes of other Tetris games, Tetris Blast also uses dominoes and trominoes.

Gameplay
Each falling piece contains at least one bomb. Most contain one bomb, not in a position horizontally or vertically between other blocks (for example not in the center of an L, J, or T), but every eighth piece is made entirely of bombs. When rows of the playfield are filled, they do not disappear as in other games; the bombs within the row explode depending on how many rows are filled at one time. It is possible for rows to be filled with no bombs, which increases the size of the next explosion.

Tetris Blast uses the sticky style of line clear gravity, allowing pieces unconnected to anything to fall. This allows chain reactions.

Whenever a piece enters the playfield, four bombs arranged into the shape of an O tetromino will become a larger bomb. Unlike in The New Tetris, these transformations happen only after the field has settled after explosions and gravity, meaning that large bombs can be formed only in rows that still have a gap. Unlike in Lumines, large bombs cannot be made of overlapping blocks.

This version of Bombliss includes three modes of play. Training allows the player to set the gravity speed, and displays four pieces in the piece preview instead of one.

In Contest, the player goes through stages with layouts of blocks, trying to clear the entire playfield to move on to the next stage. At the start of each stage, the player has 100 points. For each piece that enters the playfield, 1 point is lost. If the player runs out of points, the game ends. Creating explosions with large numbers of lines gives the player points back. When the playfield is empty, the remaining points are added to a total, and the next level starts.

In Fight, the player battles a small enemy who travels around the playfield. The enemy can cause garbage blocks to rise up by drilling into the ground, and escape enclosed areas by drilling through blocks. When a piece is placed on top of the enemy, it is flattened and slowly float through the blocks above it until reaching an empty space. To attack the enemy, the player must set off explosions that hit it, to reduce its life bar to zero. If the player can clear the entire playfield of blocks, the enemy is automatically defeated, and the player fights the next one in the roster. After defeating the last enemy (or entering a button code at the title screen), Fight 2 can be played. In this mode, the enemies are tougher, and clearing the playfield does not score an automatic win.

The game follows the partial lock out rule, meaning that if a piece locks down when any part of it is off the top of the screen, the game ends. However, this only applies to the piece in play, not to the pieces already in the field. In Fight mode, this means that even if the enemy manages to cause the blocks to rise above the top of the screen, the player can still try to lower the stack as long as no piece locks down past the top of the screen. If a line is pushed too far above the screen when the enemy creates garbage lines, it will be erased.

Explosion size table
Explosions happen when a row is filled containing a bomb, or when another explosion reaches the bomb. Each explosion is in the shape of a rectangle centered about the center of the bomb.