Crash Bandicoot?
I got a PlayStation for Christmas as a 7 year old beat crash 2-5 getting absolutely everything possible in all 4 of those games other than plantinum relics. It absolutely was the 2nd game after Pokémon I was ever very addicted to. Getting 201% through crash bash is unbelievably difficult, takes so much skill and dedication it is unreal.
I didn't find the first three Crash games to be that hard when I played them as a kid, and even easier as an adult. It's mostly annoying for how portions of it have to be done out of order.
That and the original Spyro series though are oddly satisfying.