I'd agree with kyuuei's comments--I thought it was a cavewoman, too. It's the hair and the fact that she is short and squat, with very short limbs. I think if you made her look more realistically human (she doesn't have to look like a sex kitten, though), and made the instrument clearer, and the object on fire clearer, the rest would look good. I like the side and back, too. I would use a font, rather than handwriting your name and the title, though. I think you need to make it clear to the reader that you're targeting an adult audience, even though you don't want them to have expectations of sex scenes or what have you.