Death Metal Zombies starts out with a man in a Richard Nixon mask killing people bare-handed. Then the credit sequence hits, and he basically disappears from the movie.
Brad is the biggest fan in Texas of the death metal band Living Corpse … and by extension, the world. Living Corpse announces a contest where the grand prize is a cassette with a unique song. Nowhere else in the world will this song exist. Brad bemoans his bad luck, but his girlfriend Angel and buddy Tony recommend that he enter anyway, because nobody is a bigger Living Corpse fan than he is. And he wins!
When the cassette arrives, Brad promises Angel that he won’t listen to the tape without her … but then he does, because she gets stuck working late. Brad and Tony and their buddy Kathy listen to the cassette, and its new song Zombiefied [sic]. Of course they get zombified, and the members of Living Corpse appear spiritually. The lead singer, Shengar, tells them to go forth and increase the number of followers. He also tells them to go forth and kill. These things are not as mutually exclusive as they seem.
Most of the rest of the movie is Brad and Tony and Kathy going around and killing people, several of whom rise as additional death metal zombies.
Angel comes home to an empty house with the garage door open. She goes out looking for Brad. She finds Brad. She runs away from Brad. She goes looking for the tape, but a dude named Tommy stole it. They bump into each other (literally) while escaping from the death metal zombies. They run to Tommy’s place, the zombies following behind. Death metal zombies are the slow-but-unstoppable kind.
Angel says they need to play the tape backwards. Tommy objects that he doesn’t have a machine that can play tapes backwards. But! He has a reel-to-reel. He can copy the tape to his reel-to-reel, then thread the reels backwards and play it that way.
How long will it take? Tommy doesn’t have high-speed dubbing!
The song is thirteen minutes long. Tommy and Angel will need to defend themselves from death metal zombies for thirteen long minutes using a mixture of country music and conventional weapons.
When they play the tape backwards, Shengar dissolves, and all the death metal zombies revert to their pre-zombified selves. All is well! Except for the people who got stabbed in the taint or punched through the heart or eaten alive or…. Those people are still dead.
Then ten years later, Richard Nixon mask guy converts zombiefied.wav to zombiefied.mp3 and uploads it to the early internet.
The best part of this movie (or worst, depending on your musical taste) is that it fully commits to the metal. The soundtrack is immersed in metal bands, primarily from Relapse Records. The movie credits mention eight different bands and 25 tracks.