Night Raidershd Here

Sound is often more important than sight. Always use headphones ( Comtacs ) and walk more than you run to hear enemies before they see you [17].

These are essential for unlocking new maps. You can get them from boss drops, safes, or by crafting Support smoke bombs [20]. Night RaidersHD

You can manually trigger "Veteran" status in your main menu by editing the st.txt file in your save folder and changing specific data values [11]. Sound is often more important than sight