The main challenge of this film was the gorilla itself which the story surrounds.

To be able to pull off all the details needed for the closeups required among other things, it was decided to build the gorilla entirely in CG from the ground up, including skeleton, muscles, wrinkles and hairs.

Creating the connection between the boy and the gorilla was the main challenge in terms of animation, which was keyframed throughout.

On top of animation, muscles has been simulated to get the correct skin sliding you would expect, as well as the wind in the hair.

The facial animation rig was based on the FACS (Facial Action Coding System).

Apart from the gorilla, there are set extensions and various plate cleanups and adjustments in most shots. One of the reasons for this is because of PETA's strict approach to not promote zoo's or filming live animals.