First you get the smaller annoying monkeys away by fist slamming them (a+z) then pushing them behind the the big rocks on the sides. ( you don't have to push them far behind the rocks.) Next, approach the gorilla. Be careful not to get too close or he will attack you. When he is swinging, time it just right and jump. Then, slap the ball at his belly after you do that he will swing really fast then he will swing off. After he falls of run to him and fist slam him he will get smaller and smaller untill he dies. (It takes three hits to kill him.)