Thanks for playing! If the wheel stopped at a section with blue text when you didn't receive hearts, it's because those sections increase your attack strength while the sections with red text are what give you hearts.
And as for the blue skulls, I recommend charging your shot until it's supercharged (which you can tell by the energy animation on the blaster changing twice after the initial charge animation, once to become charged and once more to become supercharged) as supercharged shots can pierce through fireballs and enemies, though I will still change the ice physics to make things more fair.