I'm fine with this specific wording to the lack of further stretch goals as it in no way prohibits them pulling some crazy moves unbeknownst to the public until such a time as they tire of gloating among themselves in secret should they actually wind up raising an extreme amount of money beyond the million dollar mark.
If they raise a bit beyond, they'll eventually mention some of the little improvements and additions that was able to get weaved into Hong Kong and the Epilogue.
If things go especially crazy by an increment greater than one or more of their normal stretch goal thresholds, there's no telling. Heh, I wonder how much Compile('s successor outfit) would want for the rights to do an enhanced remake of the Sega-CD game after all these year with all the power of their toolset for Hong Kong since that would probably be the only classic remake legally possible in theory all things considered since there's no chance beyond modders for the Genesis and SNES renditions?