Mate I can see how much work has gone into this and you did a grand job.
The movement representation works well and there is no hand visible. Image is nice regarding the contrast and conversion. The flash of silver running along where the blade begins on the lower knife image is striking.
Good concept.
On this monitor (set a little bright) the bottom left of the shot has some brush stroke marks in the black.

Excellent work, good stock image to have in your arsenal