Looking at the second video. First I think twin props are usually really really reliable. Much more than jets. And jets are really reliable. Second, maybe it's just the video, but it looks like the top side propellers aren't all there. You can clearly see the bottom propellers.
I wonder if the pilot purposefully crashed the plane in the river once he found he had no control? Because just from the looks of it, it could have been much worse. I'm just amazed people survived.