Espen’s challenge paid off. With a weekend I had some spare time to create Funkey.
Seven games on the funkey engine: climb, jumpman, invaders, drive, Doom, soar and a walk to a castle. The words in the intro are mine. The voice is not. Background music is mine and can be found on Spotify.
The weekend
Friday: a challenge from Espen: “Make a game engine for the terminal”. Saturday: the engine, real pixels through glass, then Doom. The night: sound, sprites, a 3D rasterizer, jumpman, invaders, a drive over the hills and a flight over fractal mountains. Sunday morning: a game picker with screenshots, a textured renderer on all sixteen cores, the castle, and this film.
The castle came last. Stone, slate and wood, a moat, banners in the wind, torches at the gate, crows over the keep. Twenty milliseconds per frame.
The clock
I asked, Claude built, I tested. The minutes run from my ask to the commit.
| Asked | Done | Minutes | What |
|---|---|---|---|
| 17:53 | 18:02 | 9 | the engine, and climb |
| 18:10 | 18:21 | 11 | real pixels through kitty graphics |
| 19:44 | 19:49 | 5 | frames over shared memory in glass |
| 19:52 | 20:04 | 12 | the Doom renderer: WAD, BSP, flats, sprites |
| 20:54 | 21:01 | 7 | a tap is a step, a held key is motion |
| 21:13 | 21:36 | 23 | key releases from the terminal, exact holds |
| 21:45 | 22:33 | 48 | the full Doom game |
| 23:08 | 23:11 | 3 | the Doom film, ten seconds with sound |
| 00:29 | 00:45 | 16 | sound, PNG sprites, fonts, particles, 3D, a script runner, jumpman and drive |
| 01:03 | 01:11 | 8 | jumpman’s levels proven by a checker, drive’s packages and clock |
| 01:20 | 01:23 | 3 | invaders |
| 01:31 | 01:35 | 4 | the landing page |
| 01:39 | 01:45 | 6 | soar |
| 10:09 | 10:20 | 11 | funkeys, the games as cards with screenshots |
| 10:38 | 11:14 | 36 | a textured renderer on every core, and the castle |
| 11:26 | 11:38 | 12 | the games reel, cut to music |
| 11:44 | 11:58 | 14 | the poster, the voice, the trailer |
The rest of the hours were mine: playing, looking, deciding what came next. All in between playing some pool, watching football, attending the food market downtown, general frolic.
Summary
Built with Claude Code. funkey is public domain.
- The games, on their own page
- funkey on GitHub
- From bonkers to bananas; Doom!, the post before this one
- CHasm and Fe₂O₃
Link to this post: https://isene.org/2026/09/Funkey.html
