It seems like engineers are vibe coding game ports with access to the source code

And it even has touch controls.
Tom's Hardware on MSN

Pong game recompiles its own source code every frame

The IOCCC29 winner writes each frame as fresh C source, compiles it, then runs it.
VideoGamer

Fallout 1 and Fallout 2 source code isn’t actually lost, reveals former Interplay founder, despite orders to destroy all assets

Earlier this week, we released a story that the source code and in-development assets for both Fallout and Fallout 2 were lost. According to series creator Tim Cain, and as far as he knew, the source ...
The Escapist

Hytale releases server source code and assets in Shared Source Programme

Hypixel published a new community programme sharing Hytale's Server Source Code, with select community members and modders.