I’d imagine these shots are probably just from different areas of the same dungeon. If you remember, the original Diablo, despite only having four tilesets, had a handful of different randomised "tints" for them to make them more blue, green or red and to give a bit more variety. In this case of these screenshots, perhaps as you go lower into the dungeon it takes on a more reddish tint as you get closer to the source of evil? Just a possibility.

I like the greenish color more…

These look nice. Much better looking than the green hue everywhere.

Did someone notice the big pool of blood in the barbarian pic? now more QQ about dungeons being to clean I hope. Also as I said before she looks mighty wicked in that pose with that axe ;D

If someone had told me that pink was more evil than green, I would have never believed them… that was until I saw these.

i really like how the warcry looks, and i hope we get to see many pools of blood like that one

Hmmm, nice, but actually i think it was easier to spot the monsters in the levels that had the green tint, but maybe things will be different in a gameplay video, either way we will have to wait till Blizzcon to find that out ^_^

The lighting effects and blood really help the ambiance of the dungeon. I hope things continue in that direction, and we see some more severed/impaled things. I never noticed this much before, but I like how the shadows in the Witchdoctor image seem to be responsive to the sources of light.

I assumed that was a tattered drape. The Orange glow is much better than the green.