Even to this day, I can pick up and play Pokémon Gold and have a blast.
Even after you've spent hours upon hours training your team up for the Elite Four and its champion, you have the entire Kanto region to conquer, probably doubling the time you put into the entire first region. The Kanto region is a little half-arsed if you compare it to Johto, and the you may notice the Gym Leaders' levels aren't as high as the Gym Leaders in Pokémon Red/Blue, but this isn't very notworthy when you compare it to all the good things Pokémon Gold has to offer you. Goodlooking people and Pokémon sprites, catchy music, and lots of Pokémon to battle and catch.
Pokémon Gold and Silver where the first Pokémon games to include a day/night system, with different things happening at each time of day. This all adds to make Pokémon Gold Version, still to this day, one of the deepest Pokémon games in the franchise.
Pokémon Gold Version is a great, timeless classic that hasn't aged at all.