Accept returned in 1985 as a sleeker and swifter group. It was obvious that the first taste of American success energized the band, and while Metal Heart is a more calculated and radio-friendly effort than the albums that preceded it, Accept in no way abandoned its debt to its hardcore metal base. “Up to the Limit” is a perfect example of the balance the group found between its mainstream aspirations and its fundamental aggression. While the song is more streamlined than the band's earlier work, its primary riff is as heavy as anything that came before. Happily, Udo Dirkschneider’s vocals seem to grow more feral as the production becomes slicker, as if to offset the band’s pop potential. While the album failed to produce a single on par with “Balls to the Wall,” Metal Heart was more consistent and gave fans several favorites, including the title song, “Midnight Mover," and “Living for Tonite.” Concurrently, the group experimented with new textures. “Teach Us to Survive” is a rare fusion of speed metal and jazz; it seemed to tell the audience that while Accept had mastered the art of the fist-pumping metal riff, it wouldn't be constrained by it.