I really like this being the main inspiration.
As for studio director Harvey Smith, there's only one game that came to mind when he was asked about Redfall's co-op inspirations: Dungeons & Dragons.
"I live in constant fear that people are going to figure out that we're just D&D players who think video games could be cooler and deeper," said Smith. "D&D is the best co-op game of all time, and I think people would be shocked if they knew how much we have all played D&D together as a group, from Origin Systems to ION Storm to Arkane. I am currently in three different D&D campaigns, and I still play with Ricardo on Monday nights."