There's more manipulation than enhancement here IMO. The swan pair that are not perfect mirror images of each other is a nicely believable construction. However, I think the vaguely heart-shaped void in the brush could be manipulated into a stronger, more obvious heart shape than shown here. Cropping the image so the swans and heart come closer to the focal points suggested by the Rule of Thirds might be more dramatic. Then you could apply enhancements to the result to magnify its punch.

The "shadow" of the heart shape in the bush is too solid of black, and looks obviously painted, rather than natural. You would achieve a much better effect if you cloned in the shadowed foliage from the area to the right, with a bit of the area below the "heart," then making a selection and gently lowering the brightness of it, than trying to paint it.

Great idea. It is too bad that the original image wasn't better quality but the idea is lovely! I do agree that the shadow could be a bit more subtle though.

I actually didnt at all alter the shadow--just the shape of trees around it--so the darkness of the shadow is original