The differences are pretty important, legally, when you look at each shot Rittenhouse fired compared to this guy.
First shooting: Rittenhouse was cornered by an angry, mentally imbalanced pedo who is intent on assaulting him (and stated as much)
Second Shooting: Rittenhouse, having attempted to flee (and turn himself in to police) trips and is assaulted by someone trying to kick him on the ground (this was a miss and the guy ran)
Third Shooting: Rittenhouse is then assaulted by someone else with a blunt object (skateboard), while still on the ground. That person then tries to take his gun.
Fourth: Rittenhouse, still on the ground, first decides not to shoot a guy who has a gun because the dude feigns surrender- then shoots him when the same guy tries to raise his gun again.
Each one of these was in response to an immediate threat and is a far cry from stopping, turning around and shooting at people 25+ feet away.