Just finished it. My impressions...
The map has a very nice design and polish, with plenty of ambience. I really like how the map has large wide spaces, and non linear. It just has a good clean look. It's not long (only one key card), a 10 minute romp (if you take you're time).
Enemies are a good enough challenge, but I have not played it yet on DIG, which I look forward to. However, a player can find great weapons from the beginning if they are looking for secrets. And there are plenty of secrets.
The mapping is outstanding in my view...simple enough not to get lost, but with enough places to go to keep it interesting.
Having played his maps before, I expected nothing less from Artem Nevinchany. Again, we have a map here good enough to of been in the E1 or E3 episodes. I just wish it was LONGER!
EDIT: It's no real challenge on DIG. Even though it is very short, the real problem is there is not enough enemies.