...a beat-em-up including Ninja Turtles, Battle Toads and Double Dragon...
Add Maximum Carnage-era Spider Man for the ultimate difficulty.
Games I'd want as sequels or super-modernized:
Zombies Ate My Neighbors 2
Skate or Die 3 (Fuck the Tony Hawk games. I want my stereotypical late-80s punkers.)
Pocky & Rocky 3 (Or 4 if you count P&CwB)
Tobal 3 (We'll never get two, sadly.)
A Destruction Derby game all modernized but as good as 2 was. The sequels weren't all that good.
Another Road Rash game.
The Boogerman sequel that never came out.
Ninja Golf all re-made & modernized (look it up...comedy gold.)
Another Paperboy. 64 was SHIT.
Mega Man 10 (Just for the hell of it)
Super Mario Bros. 4 (Again, for the hell of it)
Starcraft: Ghost