Geoff Crammond's The Sentinel, a tense 3D puzzle game that made the most of 8-bit computing power, was an instant classic upon release in 1986. A reconstruction of the source code is available on github, and now Mark Moxon has published a website presenting it in annotated form with historical context: "It's a lot more fun to explore than the GitHub repository, with cross-references, popups, indexes, statistics and more," he writes.
To start your journey into the secrets of The Sentinel, you might like to try the following:
See the quick start guide to find out how to use this site.
Find out how to play The Sentinel in your browser or by using an emulator.
Read more about this project and how it came to be.
Dive straight into the source code, though you might want to read these notes first, which explain some of the terminology used in the commentary.
Jump straight to a random routine from the source code – who knows where you might end up? You can also click the ∞ at the top of the page to keep jumping through the source code; it's a good way to explore.
There's much more to see at Moxon's Software Archeology.
I'm a big fan of that eerie lowpoly "the world is a lethal puzzle" subgenre. My first deep dive into to it was an Amiga game, Archipelagos (previously at Boing Boing), though many early 3D first-person games fall into it by default as there wasn't enough grunt to make other genres feasible. For example, Total Eclipse and other Freescape games hint at the Tomb Raider era of gaming, but when you have 1 frame per second, puzzles and mazes it is.
