The environment isn’t just about gathering resources and hunting. It is also a powerful weapon or tool for combat. Staying underwater allows you to approach undetected. They won’t be able to see you stalking through high grass or dense jungle, or climbing vines and ledges to try different approaches to combat scenarios. If you are detected, you can disappear into the jungle or dive into the water, causing the enemy to initiate a search. Done right, you can double back on the enemy and regain the element of surprise. – Mark Thompson, Lead Level Designer