Updating Gun Rocket through 10 years of Unity Engine

A stubborn relic refuses to wake

Ten years after building Gun Rocket, the creator tried to boot the game and it simply refused to launch. No crash log, no clue — just silence. What do you do when your own indie hit turns into a paperweight? He decided to roll up his sleeves and migrate the project forward into 2026, and invited readers along for the ride. The emotional tug is obvious: pride, annoyance, a little nostalgia — and the quiet panic of a once-viable build that won’t even spit out an error.

From humble prototypes to a paid title

Gun Rocket started as an experiment after five prototypes on Game Jolt and grew into a month-long labor with 100 levels, multiple ships and LAN multiplayer. It has been reported that after a successful Steam Greenlight run the developer was approached and licensed Steam distribution rights for several years — a tidy indie success story. That makes the failure-to-launch sting a bit sharper; this isn’t some abandoned hobby project, it’s a revenue-making artifact of an earlier career.

Versioning: the saga nobody asked for

Opening the project revealed ProjectSettings/ProjectVersion.txt: m_EditorVersion: 5.5.0f3. Git history shows development in 4.6.0p1, with a later attempt to migrate to 5.5 in 2018. Then came Unity’s naming detour: it has been reported that Unity switched to year-based version names around 2017 to make long-term support messaging easier, and later returned to large numeric identifiers (think 6000.4.1f1). The change is trivial until it isn't — suddenly finding and running the original editor becomes a treasure hunt through Unity Hub’s archive. He notes the archive only goes back to Unity 5, so his 4.6-era history lived in that basement back room — lucky he’d upgraded before.

The migration begins — and the headaches, too

He booted Unity 5.5.0f3 from the archive and hoped for the best. No dice: the editor also closed without writing a log, mirroring the broken build. Google searches were next. The story is now a familiar one to long-time Unity devs: engine churn, platform API rot, and the slow creep of bit-rot across a decade of tooling changes. The post is less about neat final answers and more about the journey — a practical log of migration steps, Unity tips and the small, telling moments that show how much game tooling has changed. Stay tuned: this is the kind of hands-on archaeology that other devs will thank him for.

Sources: jackpritz.com, Hacker News