If you find yourself surrounded by some parasites of Los Ganados or los Illuminados and do not want to waste ammunition, quickly throw a flash grenade. Once it explodes, it should make the parasites explode, saving your other ammunition.

After completing Separate Ways you will unlock the armor suit for Ashley. Press Plus to make her wait and run a short distance away. If an enemy tries to pick her up in the suit they will fall down, as if they were shot in the leg. When this happens, run up and attack them with your knife until they get up. You can also use her to distract enemies and take them on one at a time.

When playing through the game under the Professional difficulty, you may find yourself running out of ammunition just before a part where you desperately need it. When this happens, run back to a merchant and upgrade your weapon's "Capacity". This will refill your clip with extra ammunition, giving you a full chamber.