The poster above, which I found on Google Images, sums up this movie just swell, but I'm going to give my thoughts anyway.
Zombeavers is a one-trick pony with a broken leg. It's one trick is the titular undead dam-builders, and its broken leg is the horri-bad cast. Where the hell did they get these actors? Burger King? Sam's Club? Porn Hub? Not even Zeke from Disney XD's Zeke and Luther could save this pile of offal.
I get it. Zombeavers is a horror spoof whose main draw is supposed to be that it doesn't take itself seriously. I understand it's suppose to be a comedy, but so was Movie 44, and we all know how awful that movie was. The movie is never really entertaining. In fact, the most fun I had with the film was the bloopers at the end, but that's kinda like saying the best thing about your buddy is when he leaves the party and you get to make fun of him behind his back. The Whack-A-Mole sequence almost made me laugh. Almost. I think I cracked a smile, but then I remembered how terrible the rest of the movie was and that meager smile died. The movie even managed to make Bill Burr unfunny. Do you know how badly you have to suck to make Bill Burr unfunny? Shame on you, Movie. Shame. On. You.
In summation: My wife tried to watch this with me, but decided to join my son in watching Power Rangers Samurai, because, when it comes to her entertainment, she has better standards than I do.
Final Judgment: Slightly more fun than having your genitals bitten off by an aquatic mammal.