I actually got the same percentage, 57%, on Zero Mission when I played that one on normal. I tried to get 100% when I played it on hard but I got fed up with some of the speed booster puzzles and an energy tank that requires some really precise space jumping (if you screw up and trigger the lazer alarms you have to leave the room and try again) so I stopped at 84%.
See 2:55 through the end of the video if you want to know what I mean
> That said, I probably never to play Super M again.
Super Metroid has long been my favorite console game, but replaying it recently I don't really think it's still the one I enjoy the most. I don't really enjoy speed running or imposing a bunch of artificial challenges on myself and playing it straightforwardly it's pretty easy now. I did enjoy revisiting it for nostalgia's sake though.
> Note: you keep spelling it "Metorid."
I know that's wrong, it's just a persistent typo, I guess.
Is this some sort of backhanded tribute to the silly "lost worlds" in the original NES game, the ones that Gunpei Yokoi and co. forgot to program out? You know what I'm talking about, right?
No, it's not that. There are some doors that you can't open until later, and they lead to some missiles/bombs/and and an energy tank. There's a little extra puzzle solving involved but it's not hard. It just ends up feeling like a contrived tease.
Here's an example, from about 6:45-7:30 (and you can watch more if you want to see what you get for backtracking). When you first pass through the area that blue orb isn't there but the gray bird fixture is. The secret door is there but it won't open. Then later you can use those pipes to backtrack and find that those orbs have appeared (after you would have already learned what they did in another area) and you can open the doors and collect the items.