Documented source code for The Sentinel on the BBC Micro (thesentinel.bbcelite.com)

Thanks to Dan Catt [1] for sharing a link to this in his latest newsletter [2], which includes a flip-book style animation of the result of him pen-plotting a number of frames and stitching them together into a video.

[1] https://revdancatt.com/

[2] https://newsletter.revdancatt.com/p/085-the-sentinel-adventu...