#13 looks nice but some details need adjusting. Can you please have a look at the notes I just posted in the general notes section. I'll copy the notes below for convenience:
1) #11 has the best O's! The O's need to look like little Records or CD's Please make the O's like #11 or it may look even better to try this with the O's http://i.imgur.com/es0AiiY.jpg?1
2) #15 has the best playback >>| button! Please make the shape of the button look like #15. Notice how the triangles touch but are not cut off. Notice how the line on the right lines up with the T below. Notice how the shape is more accurate to a real playback button. The others are too tall.
3) You can experiment with outlining the playback button and filling in the buttons with a different color. Try Red, Blue or Purple. http://i.imgur.com/kYf8Ub4.png?1 It may not look good at all but accenting the playback button with a little bit of color is an idea.