I was actually very impressed with this level. It's extremely difficult, balls to the wall and un-relenting. In other words, my idea of the perfect marathon level. The "Gauntlet" section along the canal, with the snipers constantly attacking you from above was a big inspiration for me in regards to my own level designs - It's an idea a little more developed than the standard "Open door, walk into room, shoot bad guys & leave" setup we see everywhere else. Set piece battles like this are the most memorable moments in any marathon levels for me (can we say "if I had a rocket launcher", or "If you think you're big time"...).
I often find puzzle driven levels to be a bit dry and frustrating, as there's only so much you can achieve based around the standard find the switch that opens the door setup present in the 'thon engine. I find it much more engaging when the level is primarily combat driven.
Sure, this type of gameplay has been superceeded by more modern shooters with better monster AI, but I love the relentless hordes present in marathon. Z summed it up well when he said it feels shawshbuckley. Don't ask =)
//t
