Pros:

Great atmosphere, really feels like a damaged 
   futuristic spacecraft with fires, smoke, and sparks
   placed appropriately
Custom textures to make the map stand out
Usage of  at least one alternate route in the design
Creative use of custom obstacles including damaging
   laser beams, an autoturret, retractable bridges, etc.
Good difficulty curve, with a focus on melee weapons
Usage of L4D1 survivors
Great final boss battle

Cons:

Short preview map leaves me wanting more
Some minor bugs

Conclusion:

Overall an outstanding map of very high quality.