Shrapnel City: Tier Drops
There is a tenth level on Shrapnel City called Tier Drops. To get there, go to the movie level and go to the stage with the NASA sign and the body parts with a telescope. Kill the alien with the chain gun and press [Use] on the sign. A door should appear with the caution sign that ends the level. Do not go to the stage with the ship, or this will not work.