There is another possibility other than mechanical failure or incorrect use of the slats/flaps etc that can happen to a perfectly serviceable aircraft:
The video looks from my previous experience as though the crew may have succumbed to somatographic illusion during a severe go around manoeuvre. The angle and speed of the final seconds would result from this effect.
A similar event happened in this report (
link). Look at page 43 of the report (under somatographic illusion) and the FDR data. The false climb sensation experienced by the pilot resulted in a steep dive that was only identified upon breaking out of the cloud into visual conditions. This was too late to recover the dive.
Again, I understand that this is only speculation. I am only trying to include that there is a possibility that is not caused by a wrongly configured aircraft, broken component or airport/approach aid failures. These illusions can be overpowering in their effect on the pilot, and a recognition of them often only occurs when VMC is re-established, which in this scenario would have been unlikely. The basic principle of 'trust your instruments' can be easily disregarded during high stress situations.