Never heard of this game, but given the title and the picture I'm imagining it's about someone hunting the animals of Noah's ark has to run. Though the gorilla may have sided with them due to we humans are apes too.
They're actually saving the animals from the illegal hunters and evil poachers,
that's why the animals (gorilla included) have sided with them after you save them.
(though I'm sure that's now how it work in real life)
It's a beat em up game (like Streets of Rage or Final Fight) and kinda funny.
After you free the animals, some animals will help you to defeat enemies.
For example the deers will running and attacking the enemies after you free them.
Now imagine what happened to the enemies after you're freeing elephants.
Or after freeing dinosaurs. (Well, too bad they are not in the game)