Pros:

Some interesting horde events (burning buildings, generator restarts to activate lifts)

Space shuttle themed for last 2 maps

Interesting finale(you can bounce around and float just like in space)

Cons:

Poor detail

Poor planning of routes...makes no sense why the path is as such (random ladders everywhere)

Fps lag in many areas

Error textures and purple missing textures in many areas...there was 1 house that was entirely purple @@

Conclusion:

I only wanted to play it once...no more than that. I deleted it after 1 playthrough.