You have to use a skill there.
"Bloody Square" should always work.
If you don't have this skill yet, you might want to learn it.
The skill where you shoot a shot, and then the shot shoots vertically, should also work.
(The game just crashed when I wanted to test it, so I'm not sure how this skill is called.)
I finished the game, though it's been a while, but you can ask me when you have other problems.