It doesn't matter if this movie is based on a novell. That fact alone doesn't make it good or bad. If the novell is good, you can still make a bad movie and vice versa.

I don't know how good the novell is. This movie, however, was just bad. It was boring and lengthy. And Sandra Bullock's character was very obnoxious. Her "Boy? Girl? Boy-Girl? BOY-GIRL??!!?" calls still haunt me.

I also think the movie would have been better off if it is was just a shortfilm. The whole movie could have been boiled down just to the happenings in house. No windup, no sister-drama, no mass-panic, no river journey. Just the house, the people, the tension, the mystery, the crazy guy, the climax, END CREDITS.