Look not trying to start a flame war. We really appreciate you adding the license.
Just one correction on section 6. The "deliver on request" route is 6(b), and it only applies when the program is shipped on a physical product. For downloads like itch, section 6(d) applies: the source has to be available from the same place as the builds, to anyone who downloads them, at no extra charge. So the easiest fix is to put a source zip or a repo link next to the builds on the itch page to comply with GPL. That's all I was asking for.
On whether the code is derived: thanks for confirming the asset extraction tool comes from our project. That alone means the GPL applies. For the rest, what caught my eye was the Boom Box VU row clock. It's our own fix, not original cart behavior, as we already have the correct cart behavior for this. Your builds match ours exactly as it was taken from Pezz who's port is based on ours: the 1001257 constant with its /100000 carry, 26 voices, the 0xE0 at 0x1B98, and the 0xFA tempo check with &0x0F defaulting to 8. The 0x88 handler's 0x80 fill over 0x1802–0x19FF matches too. If you wrote those independently and somehow came to the same patch, no problem. Once the source is up, I'm happy to compare and drop it if I'm wrong.
On WaterMelon, 100% get why people are angry they have every right to be myself included. its why Pezz, hpman project little man and us have been working so hard for the last several years on this. My worry is just practical, shipping the decompiled game publicly gives them a reason to go after every Paprium project, including the ones that only run on a cart people own. That's all I meant.