Where are the flying monsters?

[Tommy Gun]

If I could choose, I'd pick them into Black Plague. That would make more sense than that they fly around the caves...

When demo of Overture we're released, we tried to put the roach into place of the dog... No luck though.

i reckon the roach, the worm, and the dogs should have been in overture. While spiders and infected in the second.
Think about it, the roaches could be a new type of fauna in the the mine, just like the worms.