It’s higher up than perceived by the camera, the grenade is probably experiencing the Bernoulli effect, where a round object tends to have a parabolic trajectory while falling due to air drag

As for the cartoonish fanfare, not sure. But I don’t think it would be enough force to throw him one way or another, I was thinking the explosion more knocked his legs out from under him since it likely is an RGO impact grenade, which explains the Bernoulli effect, since that type grenade is basically a sphere.