Squat form check #2

[MrCripples]

Morning people,
Today was my first really bad day that was not caused by being an idiot outside of the gym:I got enough sleep,ate like a lion and drank my milk,but despite all that my squats didn't work out,I got up to 130 kg and on my fourth rep just didn't get up and had to get assistance to re rack the bar.Needless to say I was wounded in my soul.
Here's the squat,are there any technique fails that can have caused my failure?
YouTube
I'm sorry for my english,I'm Italian

[Jeff Illingworth]

This is a difficult video to critique. Next time, please get a video with the camera set at the same height as your hips and located to the rear 45 degree angle.

1. Get rid of the creepy guy standing behind you. The stand you are squatting in has safeties on which you can set the bar if you get stuck. To properly spot the squat, please watch this video.
2. Get your feet under the bar, your hips back, and your chest down before you unrack the bar.
3. Make sure to fix your squat grip (your wrists should not be bent the way they are) and your upper back extension.
4. I suspect your stance is off, but I can't tell from this video.
5. You are too upright and don't have enough hip drive.

[Michael Grantham]

You're going too deep. Hard to say much more than that from this weird angle and with your spotter being in the way.

[MrCripples]

I apologize for the inadequacy of the video,next time I'll make sure to provide a better one.Would you recommend to lower the weight and practice better form?Maybe pause reps?Tempo squats?

[MrCripples]

And could my excessively upright torso be caused by the relatively light weight on the bar?I mean,it's not even twice my bodyweight,maybe the actual COM of the system is not the bar.

[Jeff Illingworth]

Your upright torso is cause by having your torso too upright, not by the weight of the bar. However, having someone standing right behind you can cause a person to be more upright as opposed to jamming their butt into the other person's crotch.

Reduce the weight and work on squatting correctly at a normal speed. Don't mess with pause reps. Don't do tempo squats per se, just make sure you're moving slow enough on the way down to keep yourself tight and controlled.

[MrCripples]

Here's today squat,how does it look like?I know I good morninged the hell out of the last rep,I'm sorry about that.I also thank you immensely for your help.
YouTube

[Jeff Illingworth]

You did not good morning per se, so don't worry about that.

Keep your head down! It will also help if you fix your grip. Control your knees better. They should get to their forward location (just at or little bit in front of your toes) by the time you're halfway down and they stay there until you're halfway back up. Also, don't let them knock in on the way up.

You can also work on getting tighter and squeezing hard through each rep.

[MrCripples]

Thanks a lot,
What do you think,should I add a little weight and progress or just stay here and get my form nailed down really good?
Do you have some cues to keep the knees where they should be?
Thanks again,Mr. Illingworth

[ssansom]

Here's today squat,how does it look like?I know I good morninged the hell out of the last rep,I'm sorry about that.I also thank you immensely for your help.
YouTube

I'm probably at best going to be half correct, so wait for Jeff's response, but here goes:
1. I think your stance might be a bit too wide, which is leading your knees to cave in.
2. It looks to me that your low back is going into slight flexion over the course of the set (and maybe a little lose on your upper back too?), but I think the jarring ascent due to the knee cave is a major contributor to the rounding, and "goodmorning" affect you describe. Squeeze everything!!! Be a chain, not a spring! It's hard, it's really hard, you gotta take your breaths, and slow down a bit, maybe?
3. You're holding the bar in your hands, try to fix your grip to the recommended thumbs-around grip. Jam the bar into your back with your palms, don't try to hold it. This might not be causing any issues now, but it could lead to some nasty wrist issues, or elbow pain. (I know, I've literally done all of the things you demonstrated in this video, and have to work on them all, all the time). Good luck!