Just looked at the new website, looks great and I don't say that often about websites that are "mobile superscrollers".
The one point that raised my eyes blink was the "illegal opcodes" in C64 feature. Allthough Paul-Gardner Stephen already showed that he understands it right: C64 software can be fixed for compatibility and enhanced to take advantage of Mega65 features. Rewriting for C65-mode requires economically much more investment.
Support for illegal opcodes raises the concern again wether the Mega65 would become "too compatible" with the Commodore 64 and run in the Commodore 128 trap that there is no advantage buying one because of lack of native software.
So therefore (perhaps needless) I ask the question: Would illegal opcodes support mean that it is no longer possible to use the advanced CPU features in C64 mode?