Interview with the mysterious coder behind ZSNES — a retrospective

When you dig into the roots of modern console emulation, a few names jump out — and one of them is zsKnight, the largely anonymous developer who created ZSNES, a Super Nintendo emulator that shocked many in 1997 by running fast, running well, and even offering online multiplayer far ahead of its time. According to a recent interview published by PC Gamer, this is the first time zsKnight has spoken about it in depth after roughly 24 years. PC Gamer

I still remember downloading this emulator on my Pentium 1 computer through AOL. The emulator could run games like Super Mario World but it would be a little slow on other higher demand games. One thing I would do to make them run full speed is take the sound off, they would run perfectly then. Zsnes and Nesticle were my emulators of choice back in the late 90s... oh yes, don't forget about No$GB emulator. I will have to share some of my emulation adventures in the late 90s sometime. 

Here’s what stood out — and what it tells us about emulation, optimization, passion and the early PC scene.

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Origins & ambition

zsKnight began learning assembly when he was 16, driven by a fascination with optimization and performance. He saw that existing SNES emulators on PC ran poorly: for example, he tried one named Super Pasofami and it managed ~10fps on his machine — no sound, very little promise. PC Gamer
Rather than accept that, he set out to build something better: “I started coding everything in pure assembly — until the Windows port there was not a single line of C code in there,” he explained. PC Gamer
He wanted full-speed SNES emulation on his own PC. He didn’t fully expect to meet that goal — but he did.

It’s a powerful reminder: often the difference between “okay” and “remarkable” comes down to how deeply someone cares about squeezing every last drop of performance — especially in hardware-limited eras.

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The “snowy UI” Easter egg

One of the most iconic things about ZSNES wasn’t a technical marvel so much as a small flourish: the “snowy” animated background effect in the menu. As zsKnight puts it:

“It’s a thing I only spent like an hour working on. I think people just love Easter eggs, and it looks nice… you’re in this menu and it just feels peaceful.” PC Gamer

It’s a charming detail. Something small, maybe trivial, yet memorable. It shows how the feel of software — not just raw performance — matters. Users remember that little snow drifting across the menu as much as they remember “it just worked”.

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Netplay before netplay was cool

Arguably the most astonishing technical anecdote: ZSNES apparently implemented an early form of rollback net-code for online play, back in an era when most connections were dial-up and real-time multiplayer emulation was far from trivial.
zsKnight described:

“30 times a second, I do a secret save state. The emulator plays ahead, maybe 30 milliseconds, and whenever it gets a packet saying the controller has changed, it rewinds to that frame and replays the emulation until the current point with that new input buffer.” PC Gamer

That sounds very much like rollback netcode, which has become a gold standard in fighting-game emulators and modern multiplayer games alike — yet it was done in a hobby project in 1997-ish. It underlines how pioneering work in communities often precedes more visible commercial adoption by years or decades.

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Impact & recognition

While he was focused on the code and rarely made his identity known, the work spoke for itself: he didn’t really appreciate how popular ZSNES had become until he interviewed for a job at Electronic Arts (EA) and found interviewers already knew the software. PC Gamer
What’s more: it’s really the first time he’s ever done a full interview about ZSNES (beyond a brief 2001 article). So the retrospective offers fresh insight into a piece of emulation history many took for granted but few knew intimately. PC Gamer

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What this means for today

• For emulation enthusiasts: the story underscores that high performance often comes down to intimate knowledge of hardware and willingness to dive into low-level code.

• For developers: the “snowy UI” reminds us small touches create emotional attachment; polish and personality matter.

• For game historians: it highlights how grassroots, hobbyist software laid groundwork for much of today’s retro-play scene, online emulation, even net-play standards.

• For anyone curious about tech and culture: it’s a case study in how hidden contributors shape the things many take for granted — and how recognition sometimes comes decades later.

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My thoughts

Reading this interview made me reflect on how often software that “just works” is taken for granted — we don’t often stop to think: “Who made this, how did they do it?” In the case of ZSNES, the answer is someone quietly obsessed with speed and optimization — someone who cared enough to push boundaries when few bothered.

If you’re running ZSNES or exploring classic emulation today, remember: behind that fast-moving SNES ROM, behind that smooth menu with the snow, is someone who approached it like a technical challenge and left a mark. The hobbyist roots matter.

Also, be sure to catch the entire hour plus interview that's uploaded on Youtube! I will also have it here if you want to watch it! This is just amazing, a true legend!