The original NES wasn't exactly lacking in experimentation...
-Brilliant platformers of a kind and quality we'd not seen
-Legend of Zelda's large world adventure style of game
--Had a masterpiece on their hands and yet completely reinvented it for Zelda II
-Metroid's backtracking and such
-Kirby's absorbing powers and such
-R.O.B.
-Some fairly great Ray gun shooters (I realize these already existed but Nintendo made them rather fun)
-Their power glove and the "compatible" games (obviously it was crap but it was certainly experimental)
-Their power pad for games that made you jump and run
It really seems like their first entry into the console market was among their more inventive and experimental, if not their most. Heck, it was during this stretch that they invented the game boy... Obviously some of that is hardware but they released games to be used with it.
