LogFAQs > #967395949

Super Mario Bros. for me. My thoughts:

The Legend of Zelda

There's still some fun to be had here with a few good dungeons and the occasional rewarding exploration, but that's about it. The game is far too cryptic for its own good and many design choices were clearly made just to sell guides. Blowing up random walls with zero environmental clues as to why they would be bombable is bad game design and not fun.

Metroid

Metroid is my favorite series in gaming, but oooof. The original Metroid is easily the option I'd want to play the least. Brilliantly ahead of its time with non-linear level design and atmosphere, but a few baffling design decisions ruin the entire game. The biggest for me is easily the death/respawn system: when you die, you start with almost no health and have to manually replenish it. Every single time. The game quickly devolves into a spamming enemies for health simulator. Also, Zero Mission exists.

Super Mario Bros.

Still a classic that's fun to pick up and play any time. Floaty physics might take a little getting used to, but they're really not that difficult once you get the momentum down. While Zelda and Metroid were more experimental, let's not deny the experimental nature of SMB 1 either with its plethora of secrets - something very few games had done at this point and none to the degree of SMB.

I can see people voting for Zelda and Metroid if you grew up with them and know them like the back of your hand, nullifying many of their flaws. But even then, I've always found that Mario is just more fun to play.