Pay attention to Max's interests (notes, TV's. radio's) and they will provide valuable information.
A moving target is harder to hit. Therefore, when engaging in gunplay use all of your evasive moves to help you avoid getting hit.
Crouching makes you a smaller target and thus harder to hit. Also, when you need to reload find an obstacle you can hide behind to avoid getting hit, and once reloaded come out blasting. And if you need a steady hand when shooting the sniper rifle, crouching will take care of that as well.
You're only making the game harder for yourself if you do not utilize the Shootdodging and Bullet Time features. Utilizing these features will give you a leg up on the competition, allowing you to aim more accurately while at the same time taking less damage.
Leave no stone unturned, or for that matter drawers, crates, cabinets, lockers, beds, etc. You'll be rewarded with pain pills, ammo, and other goodies if you take a little time to explore your environments.
Warning: Cheat keys are not officially supported by Take 2 Games. Using cheat keys can cause the game to malfunction or crash. Use at your own risk!
Unlock all levels: Play the game until you have completed the 1st subway level. Once the next level loads, go to the Main Menu and press Up, Down, Left, Right, Up, Left, Down, Circle. Proceed to the Load Menu and all levels will be unlocked. You will start each level with the same inventory you had when you completed the 1st subway level.