Harder than other puzzle games

It's a bit harder than other puzzle games. First off, you can't clear squares! In other games, there are items like mirror balls that clear items, and you can combine them with bombs to replace them with bombs, but for some reason, in this game, you select two pieces to clear them... Isn't that the same as a rocket?! I feel like there's quite a bit of luck involved too (this is just my feeling, so don't rely on it too much). It's challenging but difficult.