Several times near the end of the film the hand guns are obviously out of ammo, but are not in the next shot. This happens, for instance, when Uri is shooting in the bedroom, and again when Marshall is using the gun in the living room.
The tattoo on Uri's hand spells his name as Yuri.
The second time Amy feeds Frankie, she gives him canned food. When Marshall brings her back to the cabin, the crumbs left in the cat dish are from dry food.
Filmed in New Zealand but all cars have driver side on left.