Sound effects are usually not mandatory, even though the one inside of speech bubbles should be translated as actual speech. About your typesetting, I think the font choice is a little small, you should use something more thick or increase slightly the font size. Other than that, it's nice. Also, on page 15, top right, I think you accidentally moved the text box right because it's completely out of the bubble. On page 15 too: Masterbate -> Masturbate