Besides the overall moodiness of the title, you'll also notice the action is very fast. Most first person shooters these days are erring towards the side of realism. Look at something like Halo where you can only carry two weapons at once. Running speeds have slowed down. Jumps are shallow, sometimes even non-existent. In Painkiller, the running and jumping remind me of games like Quake and Daikatana. A more recent example would be Serious Sam.

The graphics engine powering Painkiller does more than simply paint scary environments. It is also quite interactive. Ricochets into the sides of buildings will cause pieces of concrete or rock to fly out and fall down. Jumping off a ledge and landing hard will cause your vision to be momentarily blurred from the shock. As well, the developers have a good sense of visual style too. Once you collect enough spirit powers, you attain this Predator-like sense that turns everything into black and white. Your abilities are amplified, sounds are muffled but the enemies are all highlighted in red making them easier to see.

For now, the game doesn't appear to have a significant amount of dialogue to carry through for the story, but do keep in mind that previous titles like Serious Sam had a simple backdrop to lend credence to the game. Painkiller may be seeking to the same. It has similar mechanics, particularly on the single player side where 'boss' characters populate the end of levels and numerically superior enemies are frequently thrown at you.