A landmark in the development of role-playing games is celebrating an important birthday.

Final Fantasy IV released in Japan for the Super Nintendo Entertainment System (called the Super Famicom there) on July 19, 1991. That is 25 years ago today. Fans of the series and role-playing games consider it one of the most classic entries in the genre ever made, being remarkable for its emphasis on story and moving music. Square Enix has update it for multiple platforms (console, PC, and mobile), and the original Super Famicom version alone sold over 1.4 million copies in Japan. Across all platforms and territories, it has sold over 4 million copies.

Final Fantasy IV didn’t come out in the U.S. until November 23, 1991. Here, publisher Squaresoft called it Final Fantasy II. At the time, the original Final Fantasy was the only one released in our country.

Final Fantasy IV was the first 16-bit entry in the series. Previous Final Fantasys were on the 8-bit Nintendo Entertainment System. While it had graphical improvements, Final Fantasy IV’s biggest innovation is the Active Time Battle system. At the time, most role-playing games were turn-based. You’d take a turn to attack, and then the enemy would strike, and so on. The ATB system gave each character a meter that would fill up based on their stats. You could only perform an action when it filled. The series used this system up through Final Fantasy IX. Because of its appearance in games like this and Final Fantasy VII, its become one of the famous battle systems in RPG history.

Story elements were also relatively light in the series before 1991, but Final Fantasy IV had the franchise’s first memorable tale. The story was filled with redemption, betrayal, sacrifice, and even a trip to the moon. It also had a legendary soundtrack from famed series composer Nobuo Uematsu, which included the melancholy track “Theme of Love.”

Final Fantasy IV was also the first entry in the series to have five party members fighting at the same time (most have three or four). While previous entries in the series allowed characters to be flexible when choosing classes and specializations, Final Fantasy IV heroes were set in specific roles like Monk and Bard.

Final Fantasy IV saw re-releases and remakes on multiple systems. Some, like the PlayStation and Game Boy Advance versions, added a few new features but kept the look of the original. A DS remake used new 3D graphics, while a later version for the PlayStation Portable used updated 2D graphics. Most recently, Final Fantasy IV is now available on iOS, Android, and Steam.

It also had a sequel, The After Years, released in 2008 and set 17 years after the original. Fans don’t regard it as well as the original, but it is fun to see the story continue.

So, if you want to experience this classic today, you should have pretty easy time finding a platform that suits you. Later entries in the series like Final Fantasy VI and Final Fantasy VII might have cast a bit of a shadow over this revolutionary RPG, but it still holds up thanks to its memorable characters and wonderful score.