Super Mario Bros.
When you think classic platformer, this is the game you should think of. Just moving back and forward, and with only simple power-ups like mushrooms and only enemies like goombas and koopas. A really fun game, which you can play for ages.
Super Mario Bros. 3
This game is like Super Mario Bros., but it has way better graphics and more complex gameplay. The graphics are still REALLY BAD, as all NES games are, but compared to Super Mario Bros., it’s pretty good. The gameplay is better too, because there are more enemies, like different kinds of koopas, more fire-shooting flowers and (I think) flying goombas.
Metroid is kinda like Super Mario Bros. 3, but there are WAY better enemies, better graphics and a better storyline, not just Mario saving Peach, again and again. It is pretty fun, also because Samus can actually shoot his enemies without a power-up, which Mario can’t do.
Mega Man 2
Mega Man 2 is a platformer that is good. It has good gameplay, but is the worst out of these Must-Have Games. I don’t see a real point to the game.