Both Activision and id have been rather vague on the subject:
“players […] are thrust into the unknown and unexpected to battle against combat troops, otherworldly forces, and the dark science created by a supernatural Nazi force hell-bent on world domination. Wolfenstein offers players an action-packed experience as they investigate the powers of a dark parallel dimension, join with resistance forces, and employ an arsenal of conventional and otherworldly weapons in attempts to annihilate the Nazi war machine.”
The game will feature a full arsenal of conventional and supernatural weapons, class-based team objective multiplayer and release plans for Xbox 360, PS3 and PC.