These are a few what i found
You can walk thru a space between barricade and APC (near Stamin-Up) and get out of the playable area
Its not really a bug but i would recomment you changing the navmesh instead of using a generated one (its not that hard to make it but it can take some time)
Double Tap 1.0 and Double Tap 2.0 CAN'T be enabled at the same time
I don't recommend putting any prop bridges (like a fence bridge in the power room) because zombies just simply stay frozen and can't cross it
If you would remake it it would be nice (i can provide a little help)

I can't see to open the debris in the starting room

This is probably broken. Sorry guys, it's been quite a long time at this point and I don't at all plan on going back to fix any of it :L