I've played RE4 all the way through 5 or 6 times. Okay, let's point out some places where RE:UC looks better. First, watch this video:
http://www.youtube.com/watch?v=PIPWGxZPs3Y
1. At 00:07, notice the zombie casting a projected shadow. RE4 didn't feature any such shadows; rather, the characters merely had the "blob beneath the feet" shadows. You'll see another such shadow at the snake boss scene. They're not throughout the game, unfortunately.
2. At 00:17, notice the shards of wood bouncing across the floor when the door was destroyed. They didn't do this in RE4, either.
3. At 00:23, notice the stump of the spinal column protruding from the zombie's neck. Characters in RE4 merely had a flat texture across their neck stumps once beheaded.
4. Nice reflection on the floor, eh? There are 2 or 3 areas in RE4 with environment mapped floors, and neither of them are as detailed as the scene here.
5. 00:26, the lightning strike casts a shadow on the wall. Also not seen in RE4. You should have noticed by now the bloom from the lightning. Pause it at 00:22 if you haven't yet. The graveyard lightning in RE4 didn't do this.
6. 00:44, see how the lighting projects a shadow of the railing? It's probably prebaked, but RE4 didn't do that, either. I'm not going to point out any more instances of this effect, but you'll see more.
7. 01:11, check out the texturing on the zombie's face. You couldn't see the outline of teeth on the RE4 characters.
8. 01:40, look at the glow aroudn the light fixtures. That's had some kind of bloom or filtering or something applied that RE4 didn't have. More shadows, and the environments are more destructible than RE4's.
9. 02:30, nice bump mapping on the snake. We saw a similar, but much more reduced effect on the Regenerators in RE4. Wasn't the Salazar boss bump mapped as well? I won't make a big deal out of this.
The new trailer, just a few notes:
http://www.youtube.com/watch?v=V8V5Tkzgmgs
1. 00:36, nice bloom. Not in RE4.
2. 00:50, bloom again. Definitely not in RE4.
3. 01:34, did we see explosions cause that kind of blinding white in RE4? I don't think we did, but I could be wrong.
4. 01:44, that definitely looks better than Leon's flashlight, even if the difference is only the bloom.