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When people talk about the greatest ROM hacks ever made, Super Mario Bros. 3Mix almost always comes up. Created by Southbird, this hack was more than just a simple remix of Nintendo’s NES classic… it became a sprawling tribute to Mario’s entire history. 3Mix included new mechanics like gravity flips, Yoshi integration, secret star coins, alternate exits, and even bosses and themes inspired by later entries such as Super Mario World and Super Mario Galaxy. It felt less like a fan project and more like an “official sequel that never was,” which explains why it has remained a fan favorite for more than a decade.
I first discovered Southbird through this very hack, and it quickly became one of my all-time favorites. You can read my full review of Super Mario Bros. 3Mix here, where I dive deep into what makes it such a standout experience. Having the chance to sit down with its creator gave me a rare opportunity to hear about the inspiration, the challenges, and the unexpected journey of a project that started as a side hobby and became a piece of ROM hacking history.
The Interview (09/08/25)
Q: (Retro Replay) What first sparked your interest in ROM hacking, and how did you get started?
A: (Southbird) The folks who were disassembling Sonic the Hedgehog 2 initially and finding all the inner secrets they could. I wanted this for Super Mario Bros. 3, which was a game I played every way possible when I was a kid, either playing it “100%” or as fast as possible. While there was not a lot to be found, perhaps the most substantial bits were the “unused bonus games.” SMB3 only had the “Spade” and “N-Spade” games implemented, but there were various bits of what was going to be six additional games. You can read about that at The Cutting Room Floor, where I put all my notes.
Q: (Retro Replay) Did you always picture yourself as a creator, or did this hobby evolve over time?
A: (Southbird) I was always creating something or other. When I was a kid, I was hand-drawing new levels for SMB3. When I was a teenager, I created a Sonic fangame Sonic Epoch that has some long stories behind it. I did not do a lot in my 20s, but then in my 30s I got involved with Vinesauce (until 2018) and that made me shift more into YouTube space.
Q: (Retro Replay) Who were some of your earliest gaming influences, and do they still shape your work today?
A: (Southbird) Super Mario Bros. 3 should be obvious from my other answers. Although any of the Super Mario Bros. games always held my interest, I also liked the old Mega Man and SNES Mega Man X series. Honorable mention to Super Metroid and Metroidvanias. I would say that nothing has replaced a solid platformer for me personally. I have never been as competent controlling in 3D space.
Q: (Retro Replay) Was there a specific moment where you realized Super Mario Bros. 3Mix was becoming something much bigger than just a side project?
A: (Southbird) The funny thing is, I did not see it as “bigger” as such. I mean, it was a big project in terms of effort, but I pretty much did treat it as a side project the whole time. I had done all my work to disassemble SMB3, and I figured I might as well do something with that. One of the first things I implemented was the reverse gravity gimmick, used in World 7, which required extensive rework in the collision code. I got myself on a pace of finishing one world a month, and I did. Then I uploaded it to Romhacking.net and didn’t really know what to expect.
It somehow just developed a life of its own, and it exploded into mainstream when Mike Matei played it. Although, devastatingly, he encountered a critical bug from a misplaced checkpoint object that was causing him to die over and over. The first update patch was then to fix what I officially called “The Matei Bug.”
Q: (Retro Replay) Do you remember the very first hack or small modification you ever completed?
A: (Southbird) I guess my childhood with Game Genie kinda counts. I was one of the nerds who read the part of the code book that taught you what the letters meant and how you could modify codes for additional effects. Going beyond the game and witnessing the effects from doing that, or invalid power-ups. My favorite was what we called “the Jugem’s Suit,” which enabled you to skip around the map at your whim. In-level, you would “swim” in the sky and even enter Goomba’s Shoe in water.
Q: (Retro Replay) What motivates you to keep creating, even when projects take months or years to finish?
A: (Southbird) My interests tend to cycle. 3Mix for roughly the first two worlds lacked discipline. If I could work full-time, these things would not take nearly as long. I just always like creating something. The issue with long-running projects is they tend to exhaust my interest for a while. Sometimes I never come back. 3Mix was the first fairly large creative project I managed to stick with from start to finish.
Q: (Retro Replay) How do you personally define success when it comes to ROM hacking?
A: (Southbird) I suppose if the creator sets out and accomplishes whatever they wanted to do. It does not have to be something on the scale of 3Mix. But I managed to do everything I wanted to in 3Mix, so definitely for me that was a success.
Q: (Retro Replay) Do you prefer to work entirely solo, or are you open to collaborations with other creators?
A: (Southbird) My one “thing” is wanting creative control. It is not that I cannot work with others, and I have. My brother actually helped make some of the player sprites and the title logo. My sister did playtesting as I wrapped it up, finding difficulty issues.
Q: (Retro Replay) What do you enjoy most about the ROM hacking community, and what do you find most difficult about it?
A: (Southbird) I am not in that community at present. But back when the Sonic 2 disassembly was going on, there were elitist personalities I would clash with. One project I showed off was chastised and dismissed as pointless, and being thin-skinned at the time, I abandoned it then and there.
Q: (Retro Replay) How do you deal with the limitations of older hardware like the NES when you want to add new features?
A: (Southbird) It depends on the limitation. Music was very limited, but I worked through it with carefully crafted MIDI files. Some things were just impossible, like trying to implement a Super Mario World style shifting maze. The NES’s one layer for tiles and sprite limits made it impossible. The effort remains in 3Mix as an unused level section.
Q: (Retro Replay) Are there design decisions in 3Mix that reflect your personal tastes or humor that fans might have missed?
A: (Southbird) 3Mix was more about Mario than me. But some levels in World Zero are as close as I could make to my childhood drawings that managed to survive.
Q: (Retro Replay) How important is feedback from the community to you once a project is released?
A: (Southbird) Very important. Without feedback, how will I know if I achieved the intended result? At least getting a couple pats on the back makes it feel worthwhile. 3Mix was a fluke. I thought a few people might check it out, and then it exploded.
Q: (Retro Replay) Do you ever revisit your old work and think about reworking or updating it for modern players?
A: (Southbird) Yes. Most especially my old Sonic fangame. It was never completed to my satisfaction.
Q: (Retro Replay) What has been the most rewarding moment for you since releasing 3Mix?
A: (Southbird) There’s a part of me immortalized in repro carts. But the most rewarding was how it connected me to Vinesauce. Even though I’m no longer associated, I’m still honored for the audience that stuck with me.
Q: (Retro Replay) How do you feel about the fact that players are still discovering and enjoying 3Mix more than ten years later?
A: (Southbird) Extremely glad. It’s rare anyone gets to create something that lives on that long.
Q: (Retro Replay) Are you currently working on any new hacks, homebrews, or game development projects?
A: (Southbird) My presence now is mostly YouTube and Twitch. Game-related projects haven’t been a priority, though I get the itch sometimes.
Q: (Retro Replay) Have you considered moving beyond ROM hacking into fully original indie game design?
A: (Southbird) Yes, that was always the dream. When I was a kid, shareware floppies inspired me. But by the time I graduated, 2D felt dead, and I went into IT instead. Now indie games thrive, so who knows. 3Mix might be the closest I ever get to the dream.
Q: (Retro Replay) Where can readers go if they want to learn more about you and follow your future projects?
A: (Southbird) My Discord server is where I’m most active. My current focus is more YouTube than hacking.
Q: (Retro Replay) Do you have any advice for someone who wants to dive into ROM hacking for the first time?
A: (Southbird) Start with 8-bit games, they’re simpler. If you’re not passionate about assembly programming, it won’t stick.
Q: (Retro Replay) If you could pass on one piece of wisdom to younger creators, what would it be?
A: (Southbird) Learn to take criticism. I’ve abandoned things because I reacted poorly to feedback. Trolls exist, but so does constructive input.
Q: (Retro Replay) If you could insert yourself into one of your hacks as a hidden character, what would you look like?
A: (Southbird) At this point, my toucan-style “Southbird” avatar would be recognizable. Though self-inserts always feel a little cringy to me.
Q: (Retro Replay) What is your go-to snack or drink during a long night of working on code or design?
A: (Southbird) Snacks vary, but coffee is the constant. I’m still sensitive to caffeine, so it helps push me over the finish line.
Q: (Retro Replay) If Nintendo gave you the chance to officially remake or expand one Mario game, which would you choose?
A: (Southbird) Super Mario World originally was going to have more SMB3-style mechanics. I’d love to see that alternate universe version come to life.
Q: (Retro Replay) If you could mash Mario with any non-Nintendo franchise in a dream crossover project, what would it be?
A: (Southbird) As a kid I imagined a Mario and Mega Man crossover. Mario with an arm cannon. Maybe not practical, but it amused me.
Q: (Retro Replay) Which video game boss, from any series, would you least want to face in real life?
A: (Southbird) RPG bosses. Heroes endure brutal punishment in those games — swords, spells, boulders. It seems like a very painful existence.
Outro!
Speaking with Southbird reveals not just the making of Super Mario Bros. 3Mix, but the personal journey of someone who never stopped creating. From childhood sketches of SMB3 levels, to dabbling with Game Genie codes, to ultimately building a ROM hack that has lived on for more than a decade, his story is one of persistence and curiosity. He was candid about criticism, about projects that got abandoned, and about how his interests cycle– but also about the satisfaction of finally finishing something as ambitious as 3Mix.
What stands out is how modest he remains about the project’s legacy. For him, 3Mix was simply a side project built from a love of Mario. For the community, it became one of the most celebrated hacks of all time, inspiring players, YouTubers, and streamers to keep returning to it year after year. Whether or not he ever revisits hacking or creates an original indie title, Southbird has already left a permanent mark on retro gaming.
If you haven’t tried it yet, you can find the official patch for Super Mario Bros. 3Mix on Romhacking.net, and you can read our full review of the hack here. To follow more of Southbird’s work, visit his site SonicEpoch.com or join his Discord community.
