He was probably shot with a .22 or .25, when it comes to professional hitmen they prefer low caliber bullets for up close and personal hits, because they are quieter and they aren't as messy. For instance, if the guy was shot with a .22 there wouldn't be an exit wound because the bullet doesn't have enough mass or velocity to make it all the way thorough the body, and if it hit a piece of bone it would have ricocheted around inside of him. Then the Coup de Gras at the end there wouldn't be any spatter because the bullet is small enough to cause a small entry hole and not cause any spatter because it has such a low mass.
Also another thing, this isn't a movie, Hollywood likes to exaggerate things to the extreme for entertainment purposes.
whether or not it passed through him the blood pressure whould still exit out the wound. So maybe there would be no blood splatter but there would still be soaking.. which i did not see. i'm also not saying this was fake, but something is missing (as far as i understand).
also..
notice the guy by the ice cream station that checked his watched and then walked away when the hitman approached. This was to assure the hit. Hitmen are counterproductive if the wrong person is kilt because it gives the hit away to the hitee and also alerts the cops of the scenerio.
also..
as the confirmation man (if he was) walked away he glanced at the hit man which is a very bad thing to do, although very difficult to do because the amateur is not familiar with a fresh death kill in seconds, so he has to see,
keep it business . You never do anything to alert; therefore, either this is a bad hitman-hire or an young organization.
NOW APPLY THIS TO ORGANIZATIONS THAT HAVE BEEN AROUND FOR CENTURIES.. humans are fuckin' animals.. don't forget it