I don't want to give too much away, but suffice to say this trailer is for a sequel to the insane, gore-filled, Japanese film Machine Girl. A new girl has taken on the responsibilities of the machine gun for an arm, and she's brought her own machine gun to boot. You'll love it:
I wish I knew it was it was like to watch this with the nonchalance of the Japanese viewer. "Mmm hmm, so there's one machine gun on her arm and one in her butt--I'm with you so far. Is that it?"