Solo coder finishes Game Boy racer built entirely in raw Assembly

A hobbyist developer has released Car Go Vroom!!!, a top down dodging game for the original Game Boy written from scratch in Assembly over roughly a year.

AI-drafted from 2 sources. This story was written with AI from the outside reporting listed under Sources, and checked by automated tools before it went up. The originals have the full detail.

A developer working under the name Costélinha has released Car Go Vroom!!!, a small top-down racing game for the original Game Boy, written entirely in Assembly rather than a higher-level language. The game appeared on itch.io and was shared to the r/retrogamedev subreddit on 5 September 2026, closing out what the developer describes as roughly a year of work.

You dodge an endless stream of oncoming cars and try to rack up the highest score you can before you crash. What makes it notable is not the design, which sits comfortably in the arcade dodging tradition, but the fact that it was built by hand in the Game Boy's native machine code using the RGBDS assembler, a toolchain still favoured by the handheld's homebrew scene for producing code that runs directly on the original 1989 hardware rather than through an emulator's shortcuts.

Why Assembly still matters on a 35-year-old chip

Writing for the Game Boy in Assembly means working directly with its Sharp CPU, its limited video memory and its tile-based graphics system, with none of the abstractions that modern engines provide. According to the itch.io page, all the game's assets and code were made by the developer, with help from the Game Boy Homebrew Discord community and specifically its asm-rgbds channel, where other developers helped debug what the page calls “countless bugs”. The developer also credits a contributor known as ISSOtm for a starter kit template and assembly libraries used in the project, a nod to how much of Game Boy homebrew still runs on shared community tooling rather than official documentation, since Nintendo never intended outsiders to write for the machine this way.

A battery-backed high score, the old-fashioned way

The game saves its high score to SRAM, the small battery-backed memory chip that some original Game Boy cartridges used to keep data after the console was switched off. That means a score persists through power cycles on real hardware, the same trick Pokémon and Zelda cartridges used decades ago to remember your progress. It is a small detail, but it signals that the developer built the game to behave like a period-accurate cartridge rather than a modern approximation of one, right down to save behaviour that most Game Boy emulators will faithfully reproduce and most players will never think about.

The developer’s post on the r/retrogamedev thread frames the release less as a technical demonstration and more as a personal milestone, mentioning that the project helped them through what they describe as a period of depression and low motivation. The itch.io page for Car Go Vroom!!! lists the game as released, with a changelog update to version 1.5 following the initial launch, and states plainly that no generative AI was used in making it.

What is still unclear

The itch.io listing does not say how long the .gb file is or detail the endless mode's scoring curve beyond the obvious survive-and-score loop visible on screen, and there is no word yet on whether the developer plans further updates beyond the 1.5 patch. Source code has reportedly been made public, though verifying its completeness against the shipped ROM would need someone in the community to check it. For now, it stands as one more entry in a long line of hobbyist projects proving that Nintendo's grey brick, three decades on, is still an active platform for people who fancy fighting a processor by hand.

Sources

• Finally published the racing game I was making in Assembly for the Game Boy (guilhermej14.itch.io)
• Discussion: Finally published the racing game I was making in Assembly for the Game Boy (Reddit)

Image: guilhermej14.itch.io