Super Mario Bros. 3Mix Review and longplay – Southbird’s Masterpiece ROM Hack

When it comes to ambitious ROM hacks, few projects can match the scale and polish of Super Mario Bros. 3Mix, created by the talented developer Southbird. Released more than a decade ago (2014), 3Mix is not simply a reworking of Super Mario Bros. 3 but a complete overhaul that pays tribute to Mario’s past, present, and even future. The hack introduces new mechanics, new worlds, and a staggering amount of secrets while keeping the charm and tight controls of the original NES classic. For many fans it is not only one of the best Mario hacks ever made but also one of the finest showcases of what ROM hacking can achieve. For those that are interested, we held an interview with Southbird, here. 

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The first impression is deceptively familiar, beginning with a nod to the iconic World 1-1. This might cause some players to groan, but it quickly becomes clear that 3Mix is far more than a simple nostalgia trip. The game unfolds into a massive tour of Mario history, with levels referencing Super Mario Bros. 2, Super Mario World, Super Mario Galaxy, and more. Each world has a distinct identity, often tied to the mechanics or style of another Mario game, and the transitions are seamless. Rather than feeling like a patchwork, the design flows together into a cohesive experience that feels like a lost official entry in the franchise.

Exploration is a major focus in 3Mix. Star Coins are hidden throughout levels, and collecting them unlocks new areas and challenges. Unlike some hacks where secrets feel unfair or impossible to guess, here they strike a balance between logic and creativity. Players are encouraged to return to earlier levels to search more carefully, and alternate exits add even more replayability. This system rewards persistence without punishing players who want to move at a steady pace. It is a design choice that shows just how carefully Southbird thought through the pacing and difficulty curve.

New Mechanics and Power-Ups

One of the most striking achievements of 3Mix is how many mechanics from other Mario games have been integrated into the NES engine. Yoshi makes an appearance in certain stages, behaving much like he does in Super Mario World, though wisely balanced so he does not carry over into other levels. Switch blocks, snake coins, and sand digging are also included, giving each world fresh puzzles and gameplay twists. There are even gravity-flipping levels that completely upend platforming expectations, offering challenges that feel experimental while still grounded in traditional Mario logic.

Power-ups are another highlight. The Penguin Suit from New Super Mario Bros. Wii replaces the Frog Suit, allowing Mario to slide, shoot ice balls, and move quickly in water. The Carrot power-up from Super Mario Land 2 makes its way into the hack as well, letting Mario float with rabbit ears. While some critics feel the bunny ears overlap with the Raccoon Suit’s abilities, they still provide variety and situational usefulness. Later in the game, the Boomerang Suit appears as a powerful tool capable of destroying enemies including Thwomps, though it is carefully limited so it never feels game-breaking.

Boss battles have been reimagined too, often pulling from across Mario’s history. New enemies and AI behaviors keep fights from becoming repetitive, and several bosses are remixed versions of characters players will instantly recognize. These additions tie into the theme of celebrating the entire Mario legacy, not just one era.

Visuals, Music, and Atmosphere

Visually, 3Mix retains the core look of Super Mario Bros. 3 but blends in elements from later games. Haunted houses, desert stages, and space levels all feel distinct, giving each world its own mood. The infamous Zero World creates a sense of unease with its eerie design, proving that even in 8-bit graphics a strong atmosphere can be achieved. The hub world is equally striking, providing a central map that ties the adventure together.

The music deserves its own mention. Many tracks are pulled from other Mario games, carefully adapted to the NES sound chip. While a few compositions may not reach the same quality as Nintendo’s originals, the effort to blend classic and new material pays off, creating an audio journey that matches the variety of the levels. It is rare for a hack to achieve this level of consistency in both visuals and sound, but 3Mix manages to do so without losing the identity of the base game.

Replay value is enormous. Between secret exits, optional challenges, and the hunt for every Star Coin, players can spend dozens of hours exploring everything the hack has to offer. There are even bonus games and Easter eggs, such as a slot machine level that references old pirate games, proving that Southbird injected personality and humor into the experience as well.

Community Response and Lasting Impact

Since its release, Super Mario Bros. 3Mix has earned near universal praise. Players often describe it as feeling like a genuine sequel, with one reviewer noting that it ranks among their top five Mario hacks of all time. The integration of mechanics from across the series impressed fans, with many calling it a technical marvel that pushed the NES further than most believed possible. Others appreciated how balanced the difficulty was, offering a fair challenge for casual players while reserving the most grueling content for optional secret worlds.

Not every element is perfect. Some fans felt the gravity mechanic could be confusing at times, particularly when level triggers were unclear. A few minor graphical glitches and enemy spawn issues have been reported as well, though none of these problems break the experience. Compared to the depth and ambition of the project, these flaws are minor distractions rather than serious concerns.

In the end, Super Mario Bros. 3Mix stands as one of the defining ROM hacks of its generation. It captures the essence of Mario while expanding it into something that feels entirely new. For players who grew up with the NES or those who simply want to see how far fan creativity can take a classic, this is essential.

You can learn more about the hack and download it from Romhacking.net or visit Southbird’s official site for additional projects and updates. You can read our other ROM hack reviews here.

Rating: 9.5 / 10 – A masterclass in ROM hacking that transforms Super Mario Bros. 3 into a celebration of the entire Mario franchise.