Nightwolve, I also played through SNES Super Mario World, in 2014. It had been... almost 20 years, since I last played it through, to completion.
I actually got stuck, at almost complete. I had to do a lot of backtracking, noticed I got all the secrets...
...
From what I recall, you can only get to 96(%) or so.
Was trying to do it without any guides, it's just that after you've beaten it and you go back to each and every level to scour it for the secret paths, alternate exits via the key, or whatever, it gets sooo damn boring... I never used to do this as a kid, I wanted to just get to the next game and enjoy something new; beating the game was considered "completed" as far as I was concerned back then. The fast paced nature with renting something every week to beat it though got me eventually regretting, thinking that I was missing out on the "full experience," not really savoring each game, so I slowed my gaming pace down, starting buying more games to own them and fully play them in time, but then I never recovered, then college came, first job, etc. In hindsight, considering all that I'm missing out on these days, I had the right idea as a kid seems like. Heh.