Kart Showdown

Same job, three models: build a racing kart game for the browser, then make it playable on a phone.

HAIKU SONNET OPUS

What did it cost?both steps, total

Haiku
$0.06
Sonnet
$1.71
Opus
$13.90

How long did it take?both steps, total, waiting time removed

Haiku
5 min
Sonnet
11 min
Opus
51 min

How much game did you get?8 extras: checkpoints, drift boost, particles, sound, saved best lap, bot rubber-banding, stuck-bot recovery, polished mobile

Haiku
0 / 8
Sonnet
8 / 8
Opus
8 / 8

All three pass the same 10 basic checks (3 laps, bots finish, results screen, restart...). The extras are where they differ.

Does it work on a phone?

Haiku
✗
crashes on load
Sonnet
✓
works
Opus
✓
works, tested in a real browser

Haiku is about 200x cheaper and ready in minutes, but needs a fix and has far fewer extras. Opus costs the most and takes the longest.

Opus ran at higher effort and Haiku got a one-line prompt, so the gaps mix model, effort and prompt. Games were tested headlessly, not played by hand. Cost and time come from the Claude Code session logs (idle gaps removed); one run per model.