When officer Moreno walks through the gate and up to the pool she is wearing platform sandals. As she is ready to leave she is wearing flats.
When the friends are dragging the body through the yard to hastily bury it, the huge exit wound on the right side of its head is briefly seen to be completely missing.
The goat's body, originally seen drifting along the bottom of the pool, is moments later seen floating on its surface. There is no valid reason why a sunk corpse would suddenly float. Gases that are the by product of decomposition will cause a corpse to float, but not within a few hours after death or over the course of a few minutes.