Pros:

-Custom puzzles and mazes
-Custom made Portal signs, and an overall Portal feel (The whole point)

Cons:

-That bridge over goo... clipping a ton, and special spawned at the bottom and took our friends down via smoker and such.
-Puzzles before the finale were a bit much, possibly making the finale it's own dealie woulda been cooler in my mind. Puzzles were fun, but having to re-do them if you died on the finale.

Conclusion:

Worth a download if you like puzzles, thought, and/or Portal. Good fun