Found Footage movies always have that one problem for me, where I really have to suspend my disbelief because the character holding the camera is getting into some serious shit and, instead of running for the hills, they decide, “Okay, I have to keep filming this. No matter what, I have to make sure I don’t have access to my hands and will have an obstruction over my eye.” So, in order to overcome that bit of logical vacation, a Found Footage flick has to keep my brain distracted with some good acting or just unbelievable suspense, where I don’t have time to let my brain do any senseless thinking.
And, for the most part, this is true of just about any movie in any genre–as long as you keep the action going and it’s entertaining, it makes up for some of the most serious flaws that exist in plotting (no one notices that Indiana Jones hangs onto the outside of a submarine under water for a couple hundred miles in Raiders, because of good editing).
Creep keeps its flaws in logic and sometimes-requires suspension of disbelief in check by being very well-acted by its lead, Mark Duplass. He plays Josef, a man who may or may not be dying of cancer who may or may not have hired a cameraman to document a day in his life under false pretenses.