How I Used An AI Coding Agent To Make A Countdown With 19 Games

🔍 Read the full analysis: How I Used An AI Coding Agent To Make A Countdown With 19 Games on ThorstenMeyerAI.com

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Developer Thorsten Meyer says he used the Claude Opus 5.5 coding agent to build and publish Altersteilzeit, a free web app for counting down working days until partial retirement, in five days. The project grew from a request for a short animated film into a site with a daily countdown, a narrated film and 19 3D games, offering a concrete account of how much direction and approval the human developer still provided.

Meyer’s account says the project began on Monday, September 28, 2026, with a request for a short film about the working and non-working phases of German Altersteilzeit in the block model. He says he approved the public release on Friday, October 2. Across that period, he reports making 24 commits, each co-authored by the agent. These details come from Meyer’s own account; no separate project records or independent confirmation were supplied.

The app asks users for the start date of either phase and their chosen model, from 1:1 to 5:5. It then calculates working days, taking account of weekdays, public holidays in the selected German federal state and entered leave, according to Meyer. Its daily view shows the remaining days, milestones and a saying; other features include calendar exports, a printable calendar and a finder for bridge days that can extend breaks.

Meyer describes a one-minute narrated film and games that map calendar time onto play. He says the app supports seven languages and five German dialects, with voice recordings, and includes a team countdown and badges. The source first refers to 15 game modes, but later describes 19 games; it does not explain whether those figures refer to different counts or versions.

What the Five-Day Build Shows

The project offers a specific example of a human-led, AI-assisted software build: a coding agent took on implementation and production tasks, while Meyer says he chose the product’s concept, tone and features and decided when releases were ready. That division matters to readers evaluating claims about AI development, because the account describes both the agent’s work and the human decisions that shaped the result.

The reported scope extends beyond generating code. Meyer says the agent helped produce translations, voice clips, sound effects, tests and the deployment pipeline, while also fixing a mobile scrolling problem. If accurate, the example suggests that an AI coding agent can be used across several stages of a small web project. It does not, by itself, establish how the approach compares with a conventional team, what it cost, or whether another developer could reproduce the timeline.

The app’s subject also gives the project a defined audience: people tracking a phased move from work to retirement. The countdown uses personal dates and leave to turn a long-term plan into a daily view, while the games recast calendar units as levels and obstacles. Meyer says that data is calculated in the browser, with no accounts, cookies or tracking. Those privacy statements are claims in the developer’s account, not an independent audit.

From Film Request to Countdown App

In Germany, Altersteilzeit is a form of partial retirement. In the block model described by Meyer, a person works for an active phase and is then released from work for a passive phase of equal length in models such as 4:4. The countdown is meant to track the working days remaining in the active phase, rather than simply count calendar days.

Meyer says he added features over five consecutive days. His timeline starts with the film, date entry and two game prototypes, then moves to the daily view, additional games and language support. Later additions included badges, a bridge-day finder, sound effects, a narrator and dialect versions. He reports that a hotfix was needed after a change stopped pages from scrolling on an iPhone.

The games use the calendar as their structure, according to the account: months and weeks form a maze, working days become emails in Mail Flood, and nights represent months in The Last Night Shift. Meyer says leave can affect gameplay, for example by providing a tailwind or reducing obstacles. He also says the game names were chosen to avoid other companies’ trademarks.

“I gave directions, made decisions and approved releases.”

— Thorsten Meyer, describing the collaboration

Details Still Need Verification

The development timeline, commit count, game count, language support and privacy practices are reported by Meyer, the app’s developer. The supplied material contains no independent testing, repository review or confirmation from the coding-agent provider. It is therefore not possible from this account alone to verify how much code the agent produced, how thoroughly the software was tested, or whether all stated features work as described.

The game tally is also not fully explained: the account mentions a game with 19 offerings, then says the game was playable in 15 modes. The article does not say whether the latter refers to an earlier build, a subset, or a separate way of counting. Meyer gives production totals for translations, voice clips and test scripts, but no cost, hours worked, error rate or comparison with a non-AI process.

The source describes privacy features, including date information placed after the “#” in a shared link, and says calculations happen in the browser. It does not include a technical audit or details about hosting and deployment. Those points remain unverified by the material provided.

The App’s Next Test Is Use

Meyer’s article says Altersteilzeit was publicly available by October 2, 2026, but the supplied account does not announce a future release, update schedule or user-testing plan. The next evidence that could clarify the project’s claims would include independent checks of the site’s calculations, privacy behavior, accessibility and support for its listed languages and games.

For readers considering the app, the practical next step is to check the live site’s current features and privacy information directly before entering personal dates. The source does not specify whether new features, corrections or additional translations are planned.

Key Questions

What is Altersteilzeit?

Altersteilzeit is a German form of partial retirement. In the block model described by Meyer, a person works during an active phase and then has a passive phase away from work, often for an equal length of time.

What does the app calculate?

According to Meyer, users enter the start of one phase and choose a model from 1:1 to 5:5. The app calculates the other date and counts working days, accounting for weekdays, public holidays in the selected German state and entered leave.

How many games does the app include?

Meyer describes 19 3D games, but his account also says the game was playable in 15 modes. It does not clarify how those two figures relate.

What did the AI coding agent do?

Meyer says the Claude Opus 5.5 agent helped with coding, testing, translations, voice clips, sound effects and deployment. He says he set the direction, made decisions and approved releases. These details are based on his account and were not independently verified in the supplied material.

Does the app collect personal data?

Meyer says there are no accounts, cookies or tracking, and that calculations happen in the browser. The source does not include an independent technical review of those privacy claims.

Source: ThorstenMeyerAI.com