Hidden Areas

• There are several hidden areas in each level, many of them containing useful weapons, ammo or treasures. You can access these by hitting the "use" button when in the right places. Hit the "use" button while running along the walls and you will find some of these secrets. There are often others behind paintings and in different colored areas of a corridor.
  
  

Shoot from Afar

• Back up when you encounter Nazi soldiers, dogs or other enemies. Dogs can attack only when they're close and soldiers do more damage the closer they get. On the other hand, you can fire fairly accurately from a distance, so it is to your advantage to back up to be safe and attack from afar.
  
  

Dodge Side-to-Side

• You can also avoid enemy gunfire better if you move from side to side or in a zigzag pattern down a corridor. If you stand in one place and fire at enemies, you are more likely to take a lot of damage.
  
  

Locked Doors

• As you advance in the game, you will encounter some doors that cannot be opened without a key. Backtrack and search rooms you may have missed on your first pass through the level to find the keys.
  
  

Sketch a Map

• One unfortunate aspect of this classic is that it was developed before in-game maps were in vogue, sot is easy to get lost in a level. Try sketching a map on a piece of paper to help you find your way and keep from running around in circles.