probably a lot more. Let's see what mobygames says.
http://www.mobygames.com/browse/games/nes/list-games/
hmm, less, so I guess mobygames doesn't have EVERY NES game catalogued, so it's of no use to us.
And to what boogie said, yeah, probably very few of all of them. But if that guy has kids (UNLIKELY HAHA AM I RIGHT GUYS) then exploring that room, figuring out which games are good on your own for the first time would be awesome.