If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Falling blocks of doom 2 is not simple to play like Tetris. It is another level of blocks. Just do your best and try to be the best.
"WASD or arrows to move (and jump)
-down or S to drop a block fast
-SPACE (and optionally left/right) to use your special power move.
ENTER , ESCAPE or P to pause the game, there you can choose to return to the menu screen."