Sub 10 minute "campaign." It's a port of The Lost Coast from HL2, which existed purely to demonstrate HDR lighting, so yeah.. The map plays fine, but it's just a map so, you'll be over and done with faster than you can finish eating your dinner, pretty easy going too, the church is an OP place to camp, infected pour out through the entrance, so you can sit on your ass and be fine.
I played this this afternoon and it's a very nice single map to play. A rather adventurous climb in which 2 bots died. Fortunately there is a recovery room to get the players back. The Monastery has nice artwork. Play is straight forward and you'll have no issues if you pick the right hold out spot. Instead of a helicopter escape a balloon or airship would have been interesting and fit the general feel. This would be a great start to an entire Monastery Campaign. So I graded it as a 5 for overall content and fun.
So give it a play and have some fun. Just watch your footing on the climb to the top. <G>