Going into it I already thought it was a rip off of, The Prophecy, w/ Christopher Walken and Eric Stoltz. Most of the action is what you saw in the trailer and the special effects just wasn't enough to carry the movie. Main reason was the character build up was weak. The rooftop shooting was very Day of the Dead-ish.
3D always makes a movie experience more intense. My Bloody Valentine is the first 3D horror movie I've seen since the 70's. (The Mask and The Creature from the Black Lagoon) There is no waiting for gore in this movie. Within the first 5 minutes there's blood, guts, severed limbs and more. Not like Hostile where they build the movie up for an hour and then the last half hour is the gore. The 3D and gore saved this movie because the realism was not up to par. I give it 4 stars for the fun factor.
Señor Del Toro has ingenuity & inventiveness which permits us to see through not his eyes but his imagination. What sights to see that brings out excited curiousities. Gracias Señor Del Toro.