SpeedsterBaller
Free arcade game · plays in your browser · made with Opus 5
SpeedsterBaller is a free, no-download arcade game that runs in any browser — no account needed. It sits across action and 3d as much as arcade. It was written by Opus 5, and the prompt behind it is printed further down this page. It works on a phone as well as a desktop.
About SpeedsterBaller
SpeedsterBaller is an endless downhill roll. A ball accelerates down a road suspended over a synthwave sunset. You steer left and right. There is no jump, no brake and no stopping.
The road is built from segments rather than a wave: a curvature is chosen, held for a stretch, then replaced. Roughly a third of it is dead straight, so there are places to settle, and turns arrive and end instead of the road sliding sideways under you forever. It also widens into breathers and narrows into pressure, and stretches of it drop out - sometimes down one side, sometimes down the middle, leaving two branches you have to commit to before you can see what is on them.
Red is what kills you. Blocks are placed one or two at a time, staggered in depth so you weave through rather than thread a single slot, with tighter arrangements mixed in: a gate you pass between, a squeeze that denies both edges. Some blocks track side to side and have to be timed. A check runs over the generated course and removes blockers until a ball-width lane exists, so a row cannot seal the road.
It is not flat. A descending grade carries long rollers, so the road rises ahead before pitching over, and where a crest falls away faster than gravity can hold the ball down it leaves the ground on its own. Roughly a quarter to a third of your time at speed is airborne, and none of it comes from a button.
Arrows or A and D. On a phone hold either side. Score is distance.
How was SpeedsterBaller made?
The prompt behind SpeedsterBaller
Eighth pass, addressing a specific report from play: the road shifted constantly yet felt identical every run, the obstacles were not laid out in a way worth playing and some were placed where they could not matter, and the separate pieces of road were not coming through. Two of those were structural rather than tuning. The road centre was two summed sine waves, which by construction drifts sideways continuously - it was never straight at any point - and repeats on a fixed period. It is now segment based: a curvature is chosen, held for a stretch, then replaced, with about a third of segments straight. Obstacle rows were previously built by carving one hole and filling the rest of the width with evenly spaced blocks, which reads as a wall with a slot and leaves most blocks far from the line the player is actually on, doing nothing. Rows are now one or two blocks staggered in depth, plus two deliberate arrangements: a gate to pass between and a squeeze that denies both edges. The rewrite broke the passability guarantee, which the audit caught: five sampled depths were sealed with a worst corridor of 0.64 against the 1.24 a ball needs, genuinely impassable. Two causes, both in the new code. Staggered placement could put three blocks close enough to seal a narrow stretch, and the guarantee scanned in 0.8 unit steps, wide enough to stride over a sealed depth without seeing it. Rows are now capped at two blocks with wider separation and the scan step is halved. Re-audited across 27,600 depths at four speeds: no impassable rows remain, worst corridor 1.31 against the 1.24 required. Forks are generated - roughly nine percent of sampled depths carry two spans with a void between them - but whether they read as separate road on screen is unverified, and stated as unverified rather than claimed. The posing harness calls a seek function that regenerates the course, which destroys the fork it has just located, so screenshots taken of forks were not of forks.
Categories and tags
Questions about SpeedsterBaller
5
- Is SpeedsterBaller free to play?
- Yes. SpeedsterBaller is free, runs in your browser, and needs no account. Nothing to download, no plugin, no sign-up — open the page and play.
- Do I need to download or install SpeedsterBaller?
- No. SpeedsterBaller runs entirely in the browser on desktop and on a phone. There is nothing to install and no launcher to sign in to.
- Which AI model made SpeedsterBaller?
- SpeedsterBaller was written by Opus 5, a model from Anthropic. The prompt that produced it is published on this page, so you can see exactly what it was asked for.
- Can I play SpeedsterBaller on my phone?
- Yes. The creator says SpeedsterBaller works on a phone as well as a desktop, with touch controls.
- Does SpeedsterBaller keep a high score?
- Yes. Any score SpeedsterBaller reports goes to the leaderboard under the game, and you do not need an account for it to count.
Version 7.0 · updated 2026-09-05