The Monkey presents an interesting premise, and I found its unusual elements entertaining; however, my attention started to wane concerning the people in the story near the conclusion. That’s not ideal considering the film’s relatively brief 90-minute length, but thankfully the ending arrives at a suitable point. Theo James delivers a decent performance—certainly the best I've seen from him. I haven't followed his career closely (just five films so far), and my initial association with him is actually linked to a rather unpleasant scene involving human waste in 'The Inbetweeners Movie'... I’m hoping this role will help erase that image from my mind, although it probably won't. The violence depicted during the monkey character's actions is striking and quite inventive; the 'accidental' nature of these events provides a diverting viewing experience. The scenes involving the red-eyed creature are genuinely what elevate the film as they should. With a more developed narrative, I likely would have really loved it.

Source on TMDB