The last 5-10 min needed to be redone
Reading the different threads I can see that quite a few had trouble with the last half of the movie, and I agree, but the last 5-10 minutes were the worst and should've been easy to "fix".
-The last typical cliché scene where the evil entity has to flash through the screen. Urgh! Why? It would've perfect to leave it on the box with the eery music (as they did before we got a flashing). Less is more.
-the look of the entity. Glad they didn't go for CGI, but the make-up and costume was terrible.
-the stupid stupid showdown. Ethan Hawke gets a call from officer "so and so" who practically says "you are gonna get murdered very soon" and he hangs up the phone and continues to watch the film. The same film the phone call before "so and so" warns him about (that the entity lives in images).
And the officer informing him of this seems without concern for his well being in that exact moment. Yes, we don't know what he did or said on the other end, but the dialog and tone of voice indicated that the filmmaker wasn't concerned about this (until the sequel).
The strength of this film is that it avoids making the lead character a complete idiot, but this last scene ruined that.
These tree offenses were the biggest weaknesses of the film.