Mine has to be Dragon Quest: Rocket Slime, a DS spin off of the Dragon Quest series that sees you playing as a slime operating a tank and rescuing the people from your town. You run around the overworld, collecting items to use as ammunition and saving money to upgrade your tank. The art and music are just as great as you’d expect from the Dragon Quest series. It made fantastic use of the DS’s dual screens. It’s also written for a younger audience, so a lot of it is just really silly and fun! Try it out for sure, I’m so sad there’s no sequel :(
Alter Ego, a 1986 DOS game that’s still one of the best life-sim type games ever made. You start out as a baby and work your way through life by making choices. They can lead to a wide variety of outcomes, including dying tragically as a child, etc… You can play it free online or they’ve made updated versions.
I haven’t been playing it since 86, but I feel like I first found this on the internet over 20 years ago and played it every few weeks for a solid decade. It’s still really impressive to me today that it has such replayability.