Looks like you are in the right way, thank you! First impressions:

- The Play button is hit to confirm every single piece move, while rewind/stop are less frequent use cases. maybe you can find a way to make the Play more relevant and easy to hit? The other two smaller, less remarkable?

- The CHECK! area looks too much like a button isn't it? It's a banner with information. Maybe smaller but with a more visible color? In the style of Danger! or New! banners. Having it smaller will give you more space to expand the Play button...