This high-res Sonic hack crams entire stages onto a single screen

So, you've just emptied your wallet on a dazzling new 4K monitor. What's the first thing you're firing up to really put it through its paces?  Gawking at every pore on Agent 47's head? Admiring every scratch on your Warzone rifle? Better yet, how about fitting an entire level from Sega's 25-year-old Sonic The Hedgehog games on a single screen?

Earlier this month coders from the Retro Engine Modding group managed to decompile the source code for Sonic Mania developer Christian Whitehead's 2013 mobile ports of Sega's original platformers (thanks, Ars Technica). While this lets the modders rebuild the game on anything from PC to the PlayStation Vita, it also opens up a whole world of opportunities to remix what are widely considered among the 'best' versions of Sonic 1 and 2.

It takes a few tweaks in a pre-compiled settings file to upscale the 90s platformers from their 320x224 limits to 1440p, 4K or any arbitrary resolution you'd like. Simple for the most part, anyway, because without a full recompile and a deeper dive into the games' source code, the vertical resolution remains locked at 240 pixels, turning Sonic's levels into long, narrow ribbons.

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Stretched across two monitors, things start to look very compressed indeed. Squint, and you might even spot Sonic on-screen.

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When it works, however, Sonic 1 and 2's sprawling labyrinths are laid bare in their entirety. It's stunning to see these familiar spaces zoomed all the way out—I grew up playing these games, but the winding rollercoaster layout of the courses made it hard to mentally map out these spaces as singular environments.

The mod also exposes the edges of a pair of games that were never meant to be rendered like this. Backgrounds (and the occasional bit of level geometry) repeat, mountains and lakes stack on top of each other, menus and level transitions are comically shrunk, and there are a few scripting issues stemming from the edge of the screen being far, far further away than the game thinks it is.

You'll need a copy of the Android or iOS editions of either game to start messing with REM's decompiler (sorry, that free Steam copy of Sonic 2 won't work here). But if you're up for the tinkering, this is a fascinating way to reframe two all-time platforming greats.

Natalie Clayton
Features Producer

20 years ago, Nat played Jet Set Radio Future for the first time, and she's not stopped thinking about games since. Joining PC Gamer in 2020, she comes from three years of freelance reporting at Rock Paper Shotgun, Waypoint, VG247 and more. Embedded in the European indie scene and a part-time game developer herself, Nat is always looking for a new curiosity to scream about—whether it's the next best indie darling, or simply someone modding a Scotmid into Black Mesa. She also unofficially appears in Apex Legends under the pseudonym Horizon.