Goofs

Jeff's facial hair is noticeably thicker in the opening coffee shop scene than it is later in the day.

The bloody mark on Hayley's forehead moves around.

When Hayley and Jeff are struggling on the roof in the final scene, the roof appears to be reflecting mid-afternoon sunlight but moments later Jeff is in silhouette against the sunset.

The surgical gloves Hayley wears alternate from being wrist-length to arm-length multiple times throughout the film. In fact, they are long gloves which can be rolled up, a detail visible in many scenes.

While Jeff is tied to the table you can clearly see the padding in his socks where the ropes are tied.

Hayley isn't seen changing the ice, yet the bag appears full whenever lifted without the bottom being dominated by melted ice (better known as water). Also, for as long as the ice is sitting on Jeff's lap, you would think that there would be a distinct discoloration, but there isn't.