Stealth is the name of the game here boys. As you sneak around barracks, garages, and other buildings picking off soldiers you'll find new weapons to add to your arsenal. While most enemies have AK47s, you might lucky enough to find a Dragunov sniper rifle or a large Minimi machinegun. Frag grenades and flashbangs are also present. Soldiers aren't the only problems you'll encounter.
Security cameras are plentiful all around the base.
If they see you for too long the alarms will sound and soldiers will be leaving their barracks to hunt you down. You can also slide down ladders to get back to the ground quickly without taking any falling damage. What initially surprised me was that when you're climbing your perspective changes from first person to third person. Not only does this show off the game's excellent player animations, but it also gives you a glimpse of what's above or below you before you reach it. Most games with real-life weapons don't have any health packs lying around in order to keep things more realistic, and to force the player to think before they act.