Can't aim diagonally downward

[Eccon5]

Hello,

Ive recently installed Hode and love the nostalgia! However, I have come to learn that it is impossible for me to aim diagonally downward with the charged green power. No matter what I try, it doesn't work. It does work for uncharged shots, however there is a level where you have to shoot a seed diagonally downward to make it grow, and only charged shots cause that to happen. So I am basically hardlocked out of progressing further.

Any idea on what might cause this and how to solve it?

[Eccon5]

To be clear, I use a keyboard to play.