Beat 'em up is lopsided in favor of Genesis. even if you don't like Golden Axe or Comix Zone, Streets of Rage 2 and Bare Knuckle 3 are two of the best games in the genre and SNES has nothing comparable outside of TMNT which both consoles have a variation of. has Splatterhouse 2 and 3 as well.
if you count only US releases, Genesis wins puzzle games. it has Klax and Shove It in addition to the Dr R's MBM and Columns
Genesis has Road Rash series for racing, but I don't think either console is particularly good in that genre. SNES probably wins on the strength of F-Zero, Super Mario Kart, and Top Gear series.
if you count only US releases, I think they're pretty close on RPGs. if you factor in Japan only releases, SNES obliterates the Genesis. I don't think any sRPG on the SNES is as good as Shining Force 2 though.
it's also worth mentioning that two of your "also notables" are two of the best games listed at all. Ristar and Gunstar Heroes are both top 10 games of the generation.
obviously Genesis wins in spaceship shooters. that's about as lopsided as SNES is for RPGs.
and this may catch flak (I dunno what the consensus is) but I think of all those Mega Man games listed, only X1 is particularly good. the rest, eh. Wily Wars is a port of the NES ones, right? so that might be okay.
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http://www.youtube.com/watch?v=npHDxSvwCE0