Don't spend too much ammo on the officers running to and fro behind the columns, some SS will come in from the next room. Grab some ammo then turn left and push two walls to get into a similar gallery this time on the outside of the columns. Shoot the SS behind them and push one of three walls to get a machine gun and some health. Don't push any of these walls outward. Now you have a machine gun you are ready for the action that follows. In the brown panel area things will develop quite differently depending on where you go. The little room with health and ammo can be a good place to stop by. Make it to the big grey stone room to get the chaingun behind a pushwall. You may get guards to open the gold key door for you, otherwise find the Gold Key past the SS in the north. Get the 1-up and enter the maze. Follow the crowns for the short cut, the chests for the long way. Once by the elevator, get the 1-up next to it. In the red brick area fight two Grosses for the Silver Key to get to the secret elevator in the south-western corner, past a third Grosse! Find lots of reinforcements in two secret rooms.