---
url: "https://www.reddit.com/r/ClaudeAI/comments/1x1mb45/opus_55_built_the_vehicles_and_physics_for_my/"
title: Opus 5.5 built the vehicles and physics for my Road Rash x DiRT mashup in about 3 days. It couldn’t crack the dirt bike
source_kind: reddit
subreddit: ClaudeAI
author: titkun
captured: "2026-10-21T19:33:16+00:00"
comment_tree: false
topics: [built-with-ai, opus, games]
summary: An indie dev used Claude Opus 5.5 and Astra 6 to build a Road Rash x DiRT game in days, but struggled with the dirt bike physics.
status: ok
---

I’ve been making games for about 25 years (mostly AAA, now indie) and wanted to see how far Claude could take a real game in a few days. The target was a mix of Road Rash (the 1991 one, yes I’m that old) and a rally game like DiRT.
Opus 5.5 did most of the heavy lifting: the 4 vehicles, the physics, drift boost, jump pads and rockets (that replaces the chains from Road Rash).
The hardest part was getting it to understand how the tires and shocks should move against the ground while keeping the whole thing fun and arcade. It kept pulling toward realistic, and realistic is not what you want when you’re hitting a jump pad at full speed.
For the look I used Astra 6. I gave it a screenshot of a benchmark visual and told it to reach at least 90% of that quality, and it ran 3 to 4 hours on most of the 5 maps. I tweaked the levels by hand in our editor. Music comes from Sandscape and ElevenLabs, and Sandscape handles the multiplayer and leaderboards.
The dirt bike is where it fell apart. I thought it would be the most fun and it ended up the jankiest. Still iterating on it.
I you want to give it a shot, it plays in the browser here https://sandscape.app/play?g=3UpDloEh