This is unfortunately due to our esteemed voice actor, Maneatstaco. He did great as the announcer but once we asked him to do the gorilla his tone became very serious and he said "I promised never again...but for this game I'll do it".
He became very method, insisting on only eating the diet of the Eastern Gorilla, importing thousands of dollars worth of leaves from the Bwindi Impenetrable Forest. I went to collect the audio files from his house and he was on his knuckles on the ground, creating the motion capture you see in the game. I dared not look into his eyes or he would think it was a territorial dispute.
We noticed once I put the audio files in that the gorilla became much more difficult. I asked him if he tampered with the file in such a way that it altered the code and he just did his grunts. He then acted like he was gaining the ability to speak (basically mimicking Caesar in Planet of the Apes) and said "KAH...NAUT....BE...TAINED!!!" He then lept at an inhuman speed breaking out his basement window. Blood went everywhere. No one has been able to contact him since, but a friend recently thought he spotted him on top of an iHop.
So unfortunately, that is the reason why the gorilla is so tanky. We needed to keep his performance in the game.