Seems like NZ's tech guys are doing a good job removing videos as they come up. So I'll add to the breakdown that was posted earlier. I only saw it once so I'm going from memory. Shooter had a GoPro on his head.
1) Video begins as shooter drives and parks on the street to the side of the mosque. There was a wall there, so there is no way anyone could have seen him coming from inside the building or court yard/lot.
2) Shooter gets out of car and 4 guns in his trunk. 2 AR's and 2 shotguns. He grabs 1 AR and 1 semi auto shotty. then walks around the corner to the front gate of the mosque.
3) No one is in the court yard/lot of the mosque so as he enters the property, no one can see him.
4) Shooter gets about 4 feet from the front door of the mosque and shoots at 1 person with his semi auto shotgun (3 rds or so) who is standing in the doorway. Person drops. Then another person emerges and while he is still 2 feet from the entrance, shoots more with the shotty (2nd person drops) until he is empty. He then drops the shotty and unslings his rifle.
5) The entry way has a corridor and not wide open immediately after entering. His rifle has a WML on it and is on it's strobe function. Walks about 7 feet in and turns to his right where there is an open door. He sees someone standing about 15 feet away and shoots at them. The person turns around and tries to run away and manages to get to the doorway closes to them, but drops. Bullet holes are seen as he is anticipating the continuation of the running in the dry wall (like Terminator 1 at the police station)
6) Shooter then turns around and door adjacent to the 1st open door is locked. He tries to turn the knob and nothing. He continues about 5 more feet down the corridor.
7) Then the corridor leads into the open prayer area, No chairs or pews or desk. He looks right while standing at the edge of the corridor opening. Sees a bunch of people huddled on the floor. He unloads. He turns and looks to his left and sees more people huddled on the floor in a group. Doesn't shoot yet, but keeps shooting at the people on the right side.

He then makes his way more toward the center of the open area and unloads to the people on the left. He then drops his mag and turns around and walks back toward the corridor. Gun is empty. He reloads and turns back to face the direction of the open floor. At this point someone trying to flee toward the corridor runs toward him and manages to knock the shooter down. But the person is shot also and seems dead (not moving). Shooter then gets up off the ground and shoots more at the crowd to the right. He then turns and shoots at the crowd to the left. Each time, we see via his GoPro he checks over his back to see if anyone else is coming. He then drops another mag and has no ammo in his rifle.
9) Makes his way back to the corridor where he dropped his 1st mag realizing that mag still had rounds in it. Bends over and picks it up. His rifle is empty the entire time. Loads the mag and starts shooting again at the crowd to the right. Gun then jams. He doesn't tap rack, but takes a few seconds to realize what went wrong and removes mag and pulls charging handle. Enters mag again and starts firing at both crowds. Gun is then empty, he drops the mag.
10) While there are still no bullets in the gun, he goes back to the corridor and picks up the other mag he dropped earlier because that to still had bullets in it. So at this point he dropped 2 loaded mags thinking they were empty. Goes back to the open floor and opens up in both directions again. Then his light falls off his rifle. About 1-2 mins has passed since he 1st entered the prayer area.
11) He walks back down the corridor toward the entrance. He looks over his shoulder and we see the stobbing WML on the floor in the main prayer area. Leaves the building and is in the court yard/lot. No one is there. He exits the gate and turns right and sees someone walking down the sidewalk. He shoots at them. Probably about 30 yards away. Then turns to his left and shoots at someone else down the side walk.
12) Drops his rifle he was using and goes back to his trunk. At this point, this is all what was shown on this video.
Again, this is from what I remember so some things maybe wrong. But finding the video is more difficult now. Like the other post mentioned, things can be learned since this was the 1st time a GoPro was used from the shooters perspective.
1) Shooter had little firearms training. Dropped 2 loaded mags. Tap/rack wasn't instinctive during his jam. Didn't loctite his WML. It fell off, so that shows his competence.
2) Shooter only had 2 mags on him. They looked like the 100rd surefire ones. Which would be the reason why his gun jammed.
3) Hiding in an open area under no concealment/cover will cause you to die.
4) If you are in an open area and no escape or cover/concealment, you have to rush the shooter. You're screwed either way. Or at least wait until he reloads or attention is off of you to rush. 1 guy managed to knock the shooter to the ground. Had there been a 2nd person to follow up, the shooting could have been stopped. Or if the entire group of 15 people rushed him, they could have overran him. But that isn't likely and takes practice.
5) There was adequate time to run once the 1st shot was fired from outside the mosque. About 30-45 seconds. Someone in the main prayer area could have jumped out the window. Not sure if there was another door on the opposite end. But I'm guessing there probably is. Hard to imagine a mosque with only 1 entrance/exit.
6) There was only 1 way into the open prayer area from where the gun shots are heard. So again, someone could have been waiting around the corner for the muzzle to expose itself and began attacking (30-45 seconds to make a decision to run or fight). Or if anyone was armed, they could have waiting for the shooter to emerge (kill funnel).
7) Apparently, no one walking outside the mosque heard any gun shots because there were people walking down the sidewalk still.

Need to train even at work. What to do when you hear gun shots. Valuable time is wasted while you decide right then and there what to do. Have a plan, or even multiple plans. What do I do if I hear gun shots and sitting on the toilet, walking to the restroom, in the lunchroom, etc... Everything now is in hindsight. But it's apparent that no one had a plan. Only guy without time for a plan would be the 1st guy who got shot when the shooter was 4 feet from the door. The 2nd guy emerged after the shooting started.
My video ended here. But I think he did go back to his car and get his other guns to go back inside and shoot more.