On this day in Japan 20 years ago, Nintendo introduced the gaming system, among the first consoles to create realistic-looking 3D worlds filled with monsters, soldiers, and blood. It’s standard game design today, but at that point, it was new and exciting.

Before the Nintendo 64’s launch, gamers were largely forced into games with pixelated graphics and basic gameplay that required scrolling around a screen and solving basic puzzles. The Nintendo 64, which notched more than 30 million units sold over its lifetime, was a sign of bigger and better things to come.

The console, which premiered on June 23, 1996 in Japan, was curvy and came with a three-pronged controller that included a D-pad for controlling characters movements on screen, a single thumb stick to do the same, and six buttons on the right side to make characters perform actions. Players could use the console to play games like Super Mario 64, a launch game that thrust Mario into a 3D world, and Star Fox 64, a Nintendo-developed game in which aircraft flew around and tried to shoot down enemies.

Nintendo made the console available in the U.S. in September 1996 for $199.

Unlike its competitors, the Sega Saturn and Sony’s (SNE) PlayStation, Nintendo used cartridges rather than discs for games. The move was viewed as a logical one for Nintendo, which reasoned that gamers for years had been using cartridges and would feel more comfortable with them.

The reality, however, was much different. As time went on, game developers found that making disc-based games—especially those running on the PlayStation—was cheaper. That, in turn, prompted third-party developers to increasingly focus on making games for the PlayStation, leaving the Nintendo 64 with fewer third-party titles than the Japan-based company (and the console’s owners) may have liked.

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Regardless, the Nintendo 64 is an iconic device. It was, after all, the last major game console with cartridges, and it arguably had some of the most groundbreaking video games of its generation. Super Mario 64, for instance, showed the value of an open-world environment that allowed gamers to freely explore a virtual world, while James Bond-based GoldenEye 007 helped popularize first-person shooters.

Nintendo also innovated by creating products for Nintendo 64 like the Rumble Pak, which brought the all-too-familiar vibrating controller to players’ hands. Developers used the feature to create a rumbling effect when characters in games were hit with bullets or got in car crashes.

The Nintendo 64 is remembered in different ways by fans and critics. Fans say that the console was a groundbreaking device that paved the way for future consoles, like Microsoft’s (MSFT) Xbox. They also say it showed game developers what was possible in gaming.

Critics, however, say the Nintendo 64 came with huge problems from the start. Nintendo’s decision to go with cartridges is one of the most common dings against the console. Critics say that it guaranteed the console would have a smaller library of third-party games and ultimately forced many gamers to look elsewhere. Those critics have also noted that Nintendo 64 titles often cost substantially more than PlayStation counterparts simply because of the higher cost of manufacturing cartridges.

But the Nintendo 64’s problems weren’t solely based on cartridges. It wasn’t uncommon to hear PlayStation fans or those who were simply disappointed with Nintendo say that they could find more real-life experiences on CD-ROM-based games, which allowed for live-action gameplay that put users in more realistic environments.

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Nintendo also got into the habit of creating too many add-on accessories for the Nintendo 64, those critics said. The accessories, called “Paks,” were designed to make playing more compelling. They ranged from the Rumble Pak to the Expansion Pak, which increased the console’s total memory and was required to play certain titles that featured more detailed imagery. There was even a Transfer Pak to let users of the Game Boy, the company’s handheld gaming device, transfer data between their handheld and the console.

In the end, to get the full Nintendo 64 experience, customers were shelling out far more cash on accessories that some would have liked.

If sales are the sole guide of success, the Nintendo 64 was a middling performer. The nearly 33 million units it sold is notably lower than the 62 million Nintendo Entertainment Systems sold and the 49 million Super Nintendo Entertainment Systems the company sold.

While the Nintendo 64’s sales were more than the Sega Saturn, which could only muster 9 million unit sales over its lifetime, Sony sold 102.5 million PlayStation units while competing with the Nintendo 64.

But sales aren’t everything. The Nintendo 64 might not have been the most popular console Nintendo would create, but it set the stage for both Nintendo and other gaming companies to deliver new gaming experiences, like first-person shooters.

Ultimately, Nintendo, realizing that the market was changing, and discontinued the Nintendo 64 in 2002 in Japan and 2003 in North America. The company went on to the less-popular (and disc-based) GameCube, but struck gold again with that console’s successor, the Wii.

Indeed, Nintendo’s trajectory in the post-Nintendo 64 era is one that shadows the consoles history: Some ups, some downs, but innovation along the way.

Happy Birthday, Nintendo 64.