Which levels aren't finished?

This info is in the “GBD2 Readme.txt” file that was included in the distribution: Levels 4 (The Sedgewick) and 8 (City Hall) aren't completed. I'm sure I've seen other levels in the game (The Overlook Hotel for one) that haven't been completed yet.

There's also some levels in the game based on the second movie, including a level where you get to wade in the River of Slime ™ that don't seem completed yet.

Oh the slime level was completed. It was just a maze of slime tunnels, some leading to dead ends that drown you in slime. Kindof a different approach to doom levels.