At some point the bear would be killed and, seeing that his own end would come, the gorilla would go into an existential crisis and would go on a long quest to find out how to avoid death. This quest would, eventually, lead the gorilla to finding an old lab from the time of the humans. In this lab there would live an old chimpanzee that has survived countless ages. When asked how he long survived, the chimpanzee would explain that the humans discovered the secret to immortality.
Alas, when asked for directions on how to achieve the same, the chimp would tell the gorilla that the process was lost to the span of time. The secret, however, could be found by making a journey to the lowest depths of a sunken part of urban jungle, wherein an old lab sits. After acquiring the gear to survive, the gorilla would dive deep into the abyss, and would make it to the lab. In the lab, the secret would be discovered and he would make his way to the surface, victorious.
Alas, as the ape ascended, he would be beset upon by a large mutant fish. A monster so terrifying that even the non-descriptions of the human writer H.P. Lovecraft wouldn’t be able to do it justice. The gorilla would fight the monster and emerge victorious, but at a cost. The secret that he had spent so long pursuing would be destroyed. Lost to time.
The gorilla would go back to the urban jungle and marvel at the world that he and the bear had built. Resigned to his inevitable death, this urban jungle would stand the test of time as a symbol to all that came after, of the might of the bear and the gorilla.
Fixed. Even a horrible writer that rips off ancient Sumerian myth needs an editor.