Comparing 2000's Enslaved to 2000's Opeth is something that can be done with a purpose. However, the first two Opeth albums are primarily distinguished by their song structure, progressive/experimental leanings, and extensive use of acoustic guitar. It's a huge reach to identify them as Gothenburg. Sure, they're from Sweden, but Forgotten Woods and the first Ulver album are much closer musically than any Gothenburg stuff. And whether anyone wants to believe it or not, Gothenburg covers the late '90s/early '00s sound that In Flames, Soilwork, Dark Tranquility and others got into, and Opeth never approached that. It's borderline silly to discuss Opeth as a Gothenburg band. Oddly enough, I think the lyrics are actually pretty in line with what you might see on a Gothenburg album. And it's not like Iron Maiden has exclusive license on dual guitar melodies anyway.
I didn't want to derail the thread, but that point was wrong on so many levels.