Yup, Mission 2 (the original Mission 1) is essentially unplayable because the devs don't seem to care about alpha testing. Hell, if they played that mission for 2 minutes, they'd realize they broke the door (and others, including the mansion door, which is essentially a mission-ender). It is sorta funny that you as the player need to manipulate the new change, making the zombies open the first sewer door for you though.
I wouldn't even call them "levels", even though they're listed as such. One's barely permissible as a "gallery room", and the other is just a test area for the eggs. To me, there's no real reason to play this update. It is impressive the devs have actually managed to update the game more than once per year this year though.