In the Tokyo Game Show demo we're introduced to "The Bouncer," a cannonball-firing weapon that can devastate enemy forces with a direct shot or send cannons bouncing around the world in search for an enemy to destroy.
BOOM video 6559
We also spot a few instances of enemies being thrown off high ledges, sending them screaming to their demise. According to the commentary in the video, the idea of kicking enemies off ledges became so core to the experience that levels were later designed with more areas to send enemies flying to their death with a swift kick to the breadbasket.
Bulletstorm--from developer People Can Fly--will kick down retail doors on February 22, 2011 for the PC, PS3, and Xbox 360.