Sprites in metroid have strange behaviour/animation

[djhworld]

When you roll into a ball in metroid the game is supposed to display a solid ball that you move around.

However the animation for this in the emulator is wrong, it keeps flickering/changing and is different when you move left/right

This is the same when you jump really high too

I think this is probably down to the sprite horizontal/vertical flipping logic.

[djhworld]

When rolling or jumping, sprites are being flipped horizonally and vertically at the same time. The commit above adds this implementation so the sprites render correctly this time