The Machine Girl
After the first few seconds of watching the trailer for "The Machine Girl", I thought "hmmm, looks interesting." Then some cheesy special effects started to kick in - but still want to watch it ^^;
From what I can make out from the trailer, the heroine has her family and boyfriend killed - and her left arm chopped off at the same time. She somehow manages to get a Gatling gun built to fit on her amputated arm which she then uses to shoot seven shades of shite out of her enemies.
The Japanese name for the film is Kataude Mashin Ga-ru [片腕マシンガール] and according to IMDB is due out next year.
May be a bit gory for some folks so beware.
High res trailer at BrightCove and images from TwitchFilm.