Bunch of Stuff

Alarm masks player noise.
Player takes damage from bullets.
Guards take damage from bullets (friendly fire).
Guards can only be knocked out if they do not see the player.
Pouncing is silent and landing after a pounce is near silent.
Player can use terminal to download map data. Once hacked the terminal starts counting down. If the player uses the terminal once the timer has reached 0 the alarm is activated.
Player can use the alarms (mask running noise, but guards at full alert).
Player can used dropped weapons (they fire on the ground).