Every scene is now oddly comical to me, but I still like the premise of the movie.
Other things just don't hold up to me, like the repair tool that they use like a weapon. So, the closest object I can compare the weapon to is a ram-set with a rotating drum magazine. In normal operation, the ram-set is essentially a firearm designed to fire a nail into a cement block with a small gunpowder cartridge. In order for it to fire, you have to press it firmly against the surface of the cement block to release the safety. The same applies to a lot of construction equipment that have gun-like qualities.
In the movie, they just fire it from the hip at the bad guys.