I'm just going to say it, Adventures of Link is objectively a horrible fucking game with apparently no direction. I've sunk 50-100 hours on the original Zelda. Maybe 5 on the sequel? 4 of them trying to find a silver lining.
I think Adventure of Link could be fixed. There's a lot of shit that's "Nintendo Hard" aka unfairly punishing. I think the bones of the thing are okay, but there's a lot to repair.
That's a bit heretical if you consider the context in which SMB2 came into being. It introduced many new concepts not present in the first SMB and stands on its own. It isn't just another side-scrolling platform, it was also way more vertical, way more scene transitions within a single level, the ability to move context between intra-level scenes, multiple playable characters, each with different abilities. It certainly influenced future SMB games (SMB3 implemented a similar-if-you-squint slot machine mechanic at level end). Similar to Zelda 2: The Adventure of Link which was also dramatically different from the first Zelda and it too influenced future Zelda games.
It's the "2nd" game. And it's just an iteration on SMB1. You can say SMB1 isn't like the previous Mario games too, like Donkey Kong and Mario Bros. on the arcade. Those aren't side-scrollers, there is no "ending" to them, they are actually different.