Turn left and go through the doorway. Collect the Rocket Launcher at the bottom of the stairs and kill the Ogre at the intersection of the winged staircase. Climb the staircase to the intersection and take the 25 Health, then return to the lower floor. Take the Shells to the right of the staircase and go through the doorway beside it. Go through the doorway to the right and climb the small staircase. Kill the 3 Grunts and 2 Knights at the top. Collect the Rockets and go through the doorway to the left. Kill the 3 Grunts and follow the corridor to the end. Turn left and kill the 3 Grunts, then follow the corridor to the end. Turn left, kill the 3 Grunts, and enter the doorway at the end of the corridor. Kill the 2 Knights and collect the Grenade Launcher. Go down the stairs to the left and kill the 3 Grunts. Collect the Nailgun in the dark wall beside the staircase. Go through the doorway on the opposite side of the room from the staircase and collect the Shells on the opposite wall.