Catcopter
A free multiplayer browser game about cats with propellers on their paws, brawling for catnip over tropical islands. The developer says the main tools were the Claude models Opus 5.5 and Fable.
Official site catcopter.com, verified Nov 3, 2026. The developer's own domain, posted by the developer as the Show HN link.
Where to play
Every platform this game is on. Links are checked against official sources; we never host or mirror games.
- Play free — official siteBrowserReleasedFree
Runs in a desktop browser. No download.
Browser (no download) · Official link verified Nov 3, 2026.
About Catcopter
Catcopter is a free online multiplayer game in the browser. Each player flies a cat with rotors on its paws over tropical islands and fights other players and critters, which the developer lists as pterodactyls, chickens and angry penguins. The site offers four modes, Catnip Brawl (everyone for themselves, grabbing catnip and knocking it out of the others), Team Battle, Steal the Chicken and Tube Race, and five cat classes, Striker, Gunship, Flak, Bomber and Mechanic; the Gunship, for example, has four paw rotors and a machine gun. You pick a name and a server (Europe or North America, or automatic by ping); there is no account and no download. The developer, who posted the game on Hacker News on 30 Oct 2026, says they had the idea in mind for a long time (the domain was registered about 13 years earlier), made it at first for themselves and friends, and calls it intentionally dorky. According to the developer, the main tools were Opus 5.5 for objects, rigging and motion, Tripo3d for some elements and Fable for CPU and networking optimisation, and the assets were all generated; much of the look and many techniques were reused from the developer's earlier 3D project flat.social. The terms set a minimum age of 13 and name Borkowski Consulting Ltd (London) as the operator.
How it was built
Partially verifiedIn the Show HN post the developer says the tools were “mostly Opus 5.5 (objects / rigging / motion), Tripo3d for some elements I struggled with and Fable for optimisation (cpu / networking)”. In a reply the developer gives “lots of props to Opus 5.5”, saying it was “incredibly good at getting the right game play feel from the start”, recommends trying large, even slightly vague prompts (the first pterodactyl came from asking it to “drop a pterodactyl there guarding an atomic bomb”, later calibrated by hand) and says the whole thing felt more like an art direction task than a technical one. Opus 5.5 and Fable are Claude models; the developer does not say which app or tool they were used through, or how much of the code they wrote. Tripo3d, a 3D asset generator, is not in our tool list; the developer says all the assets were generated and that the AI rigged the cat bodies and created their motion.
The developer says the front end is mostly three.js and the back end is Node.js with WebSockets, with the physics on the server done in Rapier. Many already-optimised elements (materials, shaders, colours, light set-ups and the general look and feel) were reused from the developer's earlier project flat.social, so the iteration on Catcopter itself took about a week. The developer recommends starting from large, even slightly vague prompts; the first pterodactyl came from one such prompt and was then calibrated by hand. The 3D assets were generated, partly with Tripo3d.
- Engine / framework
- three.js
- Languages
- Not disclosed
- Team size
- Not disclosed
- Initial build time
- About a week of iteration, reusing elements from the developer's earlier project flat.socialDeveloper ReportedHacker News (pawelwentpawel)
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“Also lots of props to Opus 5.5 - it was incredibly good at getting the right game play feel from the start.”Verification notes: AI use, the tech stack and the week of iteration come from the developer's Show HN post (30 Oct 2026, 15:29 UTC) and replies in the same thread that day. The developer names models (Opus 5.5, Fable), not a product, so the tool is recorded as Claude. The developer credits Opus 5.5 with objects, rigging, motion and the gameplay feel and Fable with CPU and networking optimisation, but does not say how much of the code was AI-written, and part of the game reuses the developer's own earlier work on flat.social; no AI code share is recorded. Modes, classes and servers come from the game's start screen and meta description; the operator and minimum age from the terms of use. The Show HN post is the earliest public date found; the developer says the game was first made for friends, so the first release date is left blank. Team size is not stated. The game was not played; the critters are game opponents, and nothing on the site describes AI-generated content during play.
Development history
The developer posts the game on Hacker News (Show HN).
DeveloperHacker News (pawelwentpawel)
Game performance
Each figure measures something different — concurrent players, owners, downloads and sales are never interchangeable and are never added together. Labels show where each number comes from.
Browser (official site)
The terms say Catcopter is free to play, with no accounts to create and nothing to buy.
No public metrics recorded for this listing.
Not publicly available: Concurrent players (site), Monthly revenue, Gross revenue.
Sales & revenue (all platforms)
Browser game — there are no downloads to count.
Reviews & rankings
Not yet reviewed by our editors.
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Not currently ranked.
No player reviews yet.
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Sources
| Source | Type | Published | Accessed |
|---|---|---|---|
| Show HN: I built a multiplayer game where you're an aerial fighter cat Hacker News (pawelwentpawel) | Social post | Oct 30, 2026 | Nov 3, 2026 |
| Catcopter: flying cat battles in your browser Catcopter | Official site | Not confirmed | Nov 3, 2026 |
| Catcopter — Terms Catcopter (Borkowski Consulting Ltd) | Official site | Not confirmed | Nov 3, 2026 |
| Official game page (language check) Catcopter | Official site | Not confirmed | Nov 3, 2026 |
