That video demonstrates what happens when you try to land in the ocean while you are fighting with hijackers which causes a sudden dip to one side, when you happen to be over a coral reef for the engine on that side to hit. Even with that, the crash was quite survivable. A large number of the fatalities were due to drowning, because people inflated life rafts while still inside, which blocked them in so they drowned when the plane sank.
This is probably not a good crash to use as a baseline for predicting what would be typical for an ocean landing attempt.
The hijackers, who were apparently young, stupid and intoxicated - forced the pilot to try to fly to Australia, even though the pilot said they didn't even have enough fuel to make it 25% of the way.
The plane ran out of fuel off the coast of Africa, and the engines died.
The pilot used a Ram Air Turbine (basically using airspeed to drive a turbine) to provide emergency power so he could land.
However, I assume the hydraulics didn't work at this stage, hence he couldn't use the flaps to slow it down.
