I basically agree with everything KBC has said, except it looks to me like your hips are breaking ever so slightly before your knees, which is good. You seem to be sitting back and down fine.
I think your stance width looks fine, but it can be hard to judge this in videos.
The biggest thing I think you should work on is your hand/elbow placement. You definitely need to get your elbows more underneath the bar, and if you can you may want to bring your hands in closer. A couple suggestions that may help this are to not wrap your thumbs around the bar and to hold the bar lower on your palm. Your wrists almost look hyper-extended, which in many cases can lead to your elbows pointing back and not down, depending on your flexibility.
One more basic pointer that I can’t tell off of the video is to make sure that you are retracting your scapulae, and keeping them back throughout the lift.
I also agree somewhat with MikeShank. Sometimes your bodies leverages will dictate your form, and you need to keep in mind that that is a lot of weight you are moving. Nevertheless, there is always room for improvement.
Finally, increasing your hip flexibility may help a bit, too.