[bombcar]

That's the biggest, the weight gone entirely unbalances the plane; if you knew exactly what happened you MIGHT be able to keep it level (and it seems they did for a bit) but eventually airspeed drops, it tips, and cartwheels (which is apparently what it did from the videos).

[Modified3019]

The aircraft hit the roof of a UPS warehouse, barely clearing it before coming down in the parking lot/junkyard nearby. So when we see it turning over in its last seconds (like the trucker dash cam video), it only had one wing at that point.

[beerandt]

Deadweight or no-weight engine is a relatively negligible problem in terms of the weight-balance envelope.

Cut fuel & hydraulic lines near that engine (that affect the other engines/ apus) (or less likely structural or aerodynamic problems) is what's going to shift this from "engine failure" recoverable problem to a global nonrecoverable one.