It looks more like a UFO-like landing than a fall, because his body doesn't move at all in response to hitting the ground. To feel like an impact, you would need to show how the body absorbs the energy of the impact. Try jumping up (allow your legs to straighten out while you're in the air), and paying attention to what your body does when you land. Your knees will likely bend, you might lean forward, you might be tempted to stick your arms out... less noticeably, your clothes, fat, hair, anything with even the tiniest bit of independence from your skeleton, will all react. Everything about the body will try to stay in motion as long as possible, until the skeleton forces it (or whatever it's attached to) to stop. Some parts might even rebound, moving back up before they settle in place. You don't have the space (or need) in this piece to depict all of these details, but showing some of this stuff would help it look much more like a fall.