RetroAchievements

First achievement, stomp a goomba in Mario bros.

I think for me it's Harvest Moon Friends of Mineral Town. Even though the triggers can be a bit bugged at times the achievements act as a great way to track progress like character events and your relationship level with people of the town. It's not super hard to check when dealing with the bachelorettes because their heart level is shown but seeing exact percentages is nice.

They have also incentivised me to play a lot NES games I may not have normally played like Abadox.

A Nintendo DS port of the original Peggle games that includes the full content of the original Peggle and Peggle Nights as well as ten additional exclusive levels. The objective is to shoot balls down a board and clear all orange pegs without running out of balls. It features a two-player "Dual mode" and over 125 total levels across both games. This version provides the same enjoyable and addicting Peggle puzzle gameplay on handheld devices.

ROM: Peggle Dual Shot (USA).nds [no-intro]

Ages ago, the Ancient Sages built the Temple of Time to protect the Sacred Realm. Ganondorf, the Gerudo King of Thieves, has Obtained the Triforce of Power and become the King of Evil. The power of the sages lies sleeping in six temples across Hyrule. The time has come for you to awaken as the Hero of Time!

This adaptation takes Link to familiar places and a few new ones. It is designed to be more difficult, more forgiving, and less linear than the vanilla game.

ROM: Zelda II - The Adventure of Link (USA).nes [no-intro] Patch location