Definitely not a "serious" action movie. It's funny, but in a "wow, this is dumb" sort of way, but it's still good.
It's a zombie/comedy/action movie, kind of like Shaun of the Dead but with zero subtlety. No chill whatsoever. And it's got everyone from CMOH recipients to Captain Kirk to hobbits to Ron Jeremey to Marcus Lutterell. Sean Astin, Randy Couture, William Shatner, Danny Trejo, Keith David, Bryan Callen, Ron Jeremy, Tim Kenned, Mat Best, Jessie Wiseman, Marcus Luttrell, Dakota Meyer and Mary Dague.
It's got the guys from Ranger Up, Article 15 and Black Rifle Coffee Company, product placements out the wazoo, shoutouts to Indiegogo donors and a bunch of other really goofy over the top stuff. Definitely worth a watch if you have a twisted sense of humor.