Smasher can only be defeated with the large ball he throws at you. To defeat him, you must pick up the ball and hit him with his own weapon four times. After getting an initial hit, you are able to pick the ball up again before Smasher reaches it. This can be done for all four hits.
Facade's only weakness is bombs and he takes five hits. Before the boss appears you can drop bombs where he spawns, the center of the room. A total of three hits can be had before the boss fully spawns. After Facade spawns, he can only be damaged when his face fully appears. However, if timed right, a bomb can be placed such that the explosion happens very shortly after his face appears. Though unnecessary, Roc's Feather is useful in this fight to avoid the tiles that fly at you.