The best place to see the shimmering is the start of the film in the alley way -look at the buildings against the light. It looks like something from The Matrix.
The UK Angel Heart has to be one of the worst DVDs I've seen. The shimmering (artefacting) is so bad I sent my disc back. The Region 1 Artisan disc is by far the superior -although not perfect. It's uncut of course and unrated (some artwork showed it as rated).