For my money: THE best game on the Sega Megadrive/Genesis.

Sega‘s very own level-grinding RPG franchise comes to full fruition in this fourth instalment of the Phantasy Star series, first released in 1993.

Phantasy Star IV: The End of the Millennium is a perfect mix of Final Fantasy-style adventuring, with a futuristic setting, great graphics, sound, and a humorous script. The combat is fantastic, with lots of detail, and decent rules, and great variety in the monsters, backdrops, and bosses. There are vehicle sections too. It’s a huge game.

Phantasy Star IV: The End of the Millennium is one of the best level-grinders/dungeon-crawlers of all time! And it’s still available on Steam.

More: Phantasy Star IV Wikipedia
Steam: Phantasy Star IV on Steam