Just down the stairs from the entry hall is this small bridge. Use the new grenade launcher to clear the zombies away, and jump down. A bit of the wall has a different texture. Shoot or axe it, and get the goodies.

When you go for the gold key, go to the back wall and dive. With this secret, the zombies will be standing still, when you grab the golden key. Less exciting, but better for your health.

Shoot the two jerks up on the platforms. This draws the bars in front of the goodies. Shoot the back wall of the Goodie Chamber ('X' marks the spot!) and you can teleport up to the platforms for more stuff.