If you do that, you may as well go the whole nine yards and do Max%, though what that encompasses would be up for debate. It could include:
• All Coins • All Enemies killed (since there is a kill counter) • Ring all bells (enjoy the mice RNG)
That's...really about it. That's the most you can squeeze out of this game.
Max% (like in most other games) would be a snore fest. The initial idea of this thread was also quite the opposite. Only the 6 golden boss coins were meant there, and contrary to the regular glitchless route, you'd abuse OoB level clears and checkpoint bell glitches, making the run quite a bit faster than normal.
However, I'm gonna route something that picks up a part of the max% idea for this year's 25th anniversary of SML2: Kill at least 1 specimen of all different enemies. I'm not sure how it will turn out, but it will have a few interesting strats not seen in any other category. Low% Coins is another long-standing idea. While 0 coins might not be possible without major glitches, I've been thinking about adding a time penalty to the final run time for every coin collected to make it somewhat competitive.