If hardcore was starting to become addicted to its own rules, St. Paul’s most intense smash-and-grab trio were having a blast figuring out how to subvert them. Zen Arcade is still hard/loud/fast, but in ways that flirt with psychedelia and folk and sounds not-yet-codified. The run on the double LP’s Side 2 alone (from the manic “Beyond the Threshold” to the lung-collapsing “Standing by the Sea“) is enough to mint lifelong zealots.