Beating Link's Awakening on my own. Was my first Zelda game, and I had played a shared file with my Mom when I first got it but we both got stuck on the second dungeon and stopped playing it for a long time. I picked it up one day bored and figured it out and eventually beat the game. I was so proud

This was before internet walkthroughs and so on and unless you had friends who had beat a game or paid for guides you were SoL.