There are several discussions here about games like Tetris. As a general advise: Four blocks form a tetromino. Always move the blocks together. If one fails to fall, move all four back. For making them disappear: Every time a tetromino fails to move further (which also leads to the creation of the next one), check each row if it is full. If any row is full, remove all the blocks in this row and move every block which is above it (smaller y-coordinate) down once. The scoreboard should be made when the rest works.