Just spent 1 hour 40+ mins to complete the tribute map with 4 people on xbox360 and all I can say is wow well done gearbox.
There are 30 waves to complete and the size of the tribute map is about 4 to 5 times the size of the level no hope in Hadley's.
Everything is there from the north lock to the south lock with medical and operations it felt like the whole colony from the film.
The xeno AI is quite good and the later level's the xeno's get really hard as they attack very quick and take a lot of ammo to take down they are like purple soldier xeno's with a different head style from MP.
I'm playing the 360 version dlc and my initial impressions of Bug Hunt:
Played each of the 3 maps once and the attention to detail is impressive. There are several preset weapon choices and then in-map you can close doors and reset defense perimeters and purchase upgrades with point scores. There seems to be a lot of possibilities as far as interacting with the environment regarding upgrades and those choices will be vital to survive the thirty (30) waves required for success. I only made it to the 4th wave but you can buy back in to the game if you have enough funds (1,000).
If you want to practice and familiarize yourself with the level you can press X for Advanced Options and set it to Offline play and play solo. Solo play won't be nearly as much fun but I'm pleased there is that option and doesn't make the dlc online only.
Looking forward to playing much more this evening after classes and hope PSN gets the dlc soon for those interested. You won't be disappointed.
Edit: you can play Solo offline but not splitscreen co-op for Bug Hunt like you can during Campaign mode.