Initial reports were of 6-7 shots. But there were, indisputably, 12 shots fired. This was something of a revelation coming out of the GJ. Nobody got up to 12 in any witness account. Only a few of the witnesses numbered the shots even near that (9 or 10, some reported) I think this person's read of the autopsy is plausible. In essence, Brown was all but butchered at the car window with multiple shots. Someone will dispute this account by noting the location of the shells near Brown's body, 140 feet away, but that's not really that compelling, since both the perpetrator and his co-conspirators had full access to the scene and plenty of time to move shell casings: the scene was not secure, so evidence like shell casing locations are more or less meaningless. There was no legitimate security of the crime scene (Wilson stalked around it for many minutes after the shooting, possibly placing shell casings from his car nearer to Brown's body).

The only other major point disputing this reading is the testimony of Dorian Johnson, who doesn't seem to believe there were more than 1 or 2 shots fired from inside the car. But we also know that he underestimated the total number of shots by almost 50%. So, we'd have to start to wonder if there was some shock coloring his account.

after being hit by one shot in the hand and chest I believe.

If a cop was moving shell casings even if you believe the cops would keep quit, why have not been any witnesses claiming shell casings were moved?

when Wilson opened the door and hit Brown with it while Johnson and Brown were right next to the car?

The real issue is whether Wilson had the intent to assault Brown when Wilson backed up the car right next to him and Johnson. At that point, Wilson had no reason to aggravate a tense situation. He should have waited for backup before trying to deal with Brown on his own.

This is a matter of poor police training.

The forensic evidence confirms Wilson's description of part of his struggle with Brown and his shooting with Brown. It is a bit of an exaggeration to say that it confirms Wilson's story. It confirms Wilson's account of the shooting part of the story but Wilson made decisions before the shooting that led to the shooting.

There was no physical contact between Brown and Wilson until Wilson backed up his car in order to initiate a confrontation. Wilson should have waited for back-up. We would have a very different story had he done so. It was at the very least a serious error in judgment, perhaps much worse. In my opinion, the case should have been sent to a jury.