Well they wrapped up the show all right. By killing off the Gunmen.

Although I personally liked those three and was upset they got offed, I personally liked the episode. I thought it was well written; there was some good foreshadowing in particular with Langley telling Fletcher about Joey Ramone and Byre's conversation w/ Frohike.
The ending was obviously taken from The Wrath of Kahn (between this and Futurama, anybody notice a heck of a lot of Star Trek references on Fox tonight?) but it was still a fitting and noble end for the three idealists. They wanted to save the day, and they did.
Damn it, I liked those guys.
