This sounds nothing like Opeth, yet it reminds me of the first time I listened to Opeth after death metal finally clicked, and this reminds me of that. Bluenothing would be more like Edge of Sanity. You have some great 90s DM worship, with a little acoustic guitar and some proggy songwriting in there, but it isn't too much. It's perfect. Worm makes some nostalgic, yet epic death metal.
Favorite track: Centuries of Ooze II.