But yeah, even if Captain N and Smash Bros are 100% opposite quality wise, you still have many properties intersecting directly or otherwise.
Super Mario Bros, The Legend of Zelda, Mike Tyson's Punch-Out, Donkey Kong, Kid Icarus, Castlevania, Mega Man, Metroid and Final Fantasy.
Specifically Mother Brain for Captain N and even served by the Dragonlord. Ganon during his appearance not so gracious.
Samus Aran for Smash, and as an aside she did appear proper in the short-lived Valiant Comics as Kid Icarus did as well. Only thing is that the third party game character weren't available. Though a letter column confirmed plans to have an appearance by Mega Man. Kid Icarus villain Uranos also was among Mother Brain's League of Darkness.
King Hippo for Captain N and Little Mac for Smash. Little Mac could probably have worked in show as a fighter, but they didn't use him, though he appeared in the brief bit of live action before Kevin was sucked into Videoland. Said bit also is in each opening.
Castlevania and Mega Man, the same as well as Kid Icarus even if Captain N used the game title name for Pit. And for those of us who watched it back then, even with it being more a guilty pleasure, it is still nice to have a game with the three as playable characters.
Additionally nice for having Sonic and Mega Man together again as their Archie Comics lines folded. Plus Ryu and Ken among them as all four were in the crossover comic Worlds Unite. Mega Man X counting if you include any sort of appearance.
Amalgam Universe resident Born in 82.