Sega's OutRun is getting a homebrew port for stock Neo Geo hardware

Homebrew developer BenDk97 has shared new details on their work-in-progress Neo Geo port of OutRun, demonstrating a 60-frames-per-second display prototype of Sega's 1986 arcade racer. First revealed earlier in October 2026 alongside a free prototype on itch.io, the project aims to run the original arcade game on stock Neo Geo MVS and AES systems without adding custom coprocessors to the cartridge.

In the current display prototype, the road calculations are not running natively on the Neo Geo's 68000 CPU; the developer stated that the frames were computed offline from the arcade game and then replayed on the Neo Geo, noting that porting the road engine to the 68000 is still planned. Even as a non-interactive attract-mode replay tested in MAME with UniBIOS 4.0, watching SNK's hardware push all those roadside palm trees at full speed is impressive.

Faking a road chip with 380 sprites

When Yu Suzuki and Sega AM2 launched OutRun in September 1986, the cabinet used a heavy-duty board to pull off its pseudo-3D hills and branching coastal highways. That arcade hardware paired two 12.5 MHz Motorola 68000 processors with dedicated sprite-scaling silicon and a custom road generator chip. Early home conversions on the Sega Genesis, TurboGrafx-16, and Commodore 64 had to make severe visual and framerate compromises because consumer systems simply couldn't match that custom board.

SNK's Neo Geo, which arrived in arcades and living rooms in 1990, has a very different architecture. It runs on a single 12 MHz 68000 CPU paired with a Z80 audio coprocessor, and it doesn't have traditional scrolling background tile layers at all.

Everything you see on a Neo Geo screen is made of vertical sprite strips, up to 380 of them at once, plus a static "fix" layer on top for HUD text. To make OutRun work on SNK's hardware, BenDk97 converts the road, scenery, trees, and traffic into Neo Geo sprites, while the text sits on the fix layer. Some visual approximations are still visible in the prototype, including checkerboard shadows and a few missing distant objects, and I'm curious to see how well the 60fps target holds up once live gameplay logic and YM2610 audio are running simultaneously on that single 68000.

From Amiga brawlers to Sega's Ferrari

This isn't BenDk97's first time forcing an older game onto SNK silicon. Working with C, 68000 assembly, and the open-source ngdevkit toolchain, the developer previously built an unofficial Neo Geo conversion of Discovery Software's 1989 Amiga action game Sword of Sodan for both cartridge systems and the Neo Geo CD. Moving from a side-scrolling Amiga brawler to a dual-CPU Sega super-scaler is a massive jump in complexity, though it fits right in with the broader homebrew trend of porting Sega arcade games like Golden Axe and Shinobi to the Neo Geo.

The ultimate goal for the project is a fully playable conversion running within the 64 KB of work RAM on an unmodified console or MVS board. Right now, the prototype hasn't been tested on physical consoles or flash cartridges, and the developer's next steps include getting the road engine running on the 68000, implementing sound, and testing the build on real hardware.