Yes, this is almost certainly a violation. Technically, you cannot be sure yet, because in some alternate universe, Nintendo might have re-licensed their SDK un

Yes, this is almost certainly a violation. Technically, you cannot be sure yet, because in some alternate universe, Nintendo might have re-licensed their SDK under GPL as well, and if you ask Limited Run Games for the source of Tomba, they might give everything to you, thereby complying with the license. In reality though, these SDKs are of course not only proprietary but also under a NDA. Alternatively, they might have found a way to run PCSX without using the Nintendo SDKs, but I don't think this is possible. It's pretty crazy that they officially credit PCSX and didn't even realize that this is a problem.