Claude rebuilt the 1989 game 'Prince of Persia' by reusing the original's own code

Amid a week of AI stories about escapes, hotlines and billion-dollar chip clusters, here is a smaller one that is easy to picture and easy to check: an AI rebuilt a 37-year-old video game.

Anthropic says its Claude Opus 5.5 model reconstructed Prince of Persia, the 1989 platform game that was a landmark of its era, and did it in a notably efficient way — by reusing the original DOS version's own routine for drawing the game's rooms rather than writing that logic anew.

Why Reusing The Old Code Is The Interesting Part

The detail that matters is not that Claude produced a working game. It is how it got there.

Reusing the original room-drawing routine means the model read and understood decades-old code, recognised which parts were worth keeping, and wove them into a working reconstruction. That is closer to how a skilled human engineer actually works — standing on existing code rather than rebuilding everything from zero — than to the pattern of an AI generating plausible-looking code from scratch. It is a sign of judgement about code, not just production of it.

It also showcases long-context coding: holding enough of an old, unfamiliar codebase in view to make coherent decisions across the whole of it.

Why A Small Story Is Worth Telling

This piece is deliberately modest, and that is the point.

Much AI news involves claims that are hard for an outsider to verify — a model that reasons better, a system that is safer, a capability demonstrated in a lab. A rebuilt game is different. It either runs and plays like Prince of Persia or it does not. It is concrete, checkable, and does not require taking a company's word for it.

In a week thick with grand and unverifiable assertions, a demonstrable result at human-legible scale is a useful thing to be able to point at.

The Honest Caveats

Two, in the interest of not overselling it.

First, the disclosure that applies to any story about an AI company's own model: this is Anthropic demonstrating Anthropic's product, and the framing is theirs. The value here is that the result is checkable in a way many such claims are not, but it is still a company showing off its own work.

Second, rebuilding a well-documented 1989 game — one whose source has been studied and republished — is a bounded, favourable task. It is a genuine demonstration of capability, not proof the same model would handle a large, novel, undocumented codebase as gracefully. It shows what the tool can do on a problem that suits it.

What It Signals

Taken for exactly what it is, the result marks how far AI-assisted coding has moved: from autocompleting lines, to generating functions, to reading and repurposing an entire old codebase into something that works.

That progression is the real story under the nostalgia. The game is the demonstration; the capability to comprehend and reuse existing software at that scale is the thing that matters for everyone who builds with these tools.

What To Watch

Whether the same reuse-and-comprehend ability holds on large modern codebases that are messy and undocumented, which is where real engineering lives. Whether developers report that current models genuinely work this way in practice. And whether checkable demonstrations like this become more common, because they are worth more than claims that cannot be tested.