another game I finished as a kid and I don't know how I did it is Sonic 1 (8 bit version)
Discussion
Quantos anos tu tem ?
I finished 100% Crash 1 as a kid
It was very hard but straightfoward, anything requiring reading I couldn't finish until teenage tho, like Megaman Legends
Then there's games like Ecco on megadrive in which I couldn't figure out what to do as a kid, or as adult. Swim around aimlessly using echolocation for 10 minutes and shut the game down, every time.
I can't recall which games, but I did go through this when I was a kid, playing without really knowing what I'm supposed to do and then give up lol