They're progressively on Amazon, starting in Kindle format (I'll have a proper paperback after I'm content with their state, later on). Roughly $6 each, up and down with time. Currently, I'm known for The Warrior Poet's Guide series, on building plug-ins for multimedia software, two on the market now—one is on plug-ins for Blender 2.80 (a very popular one), and the other on building plug-ins for GIMP 2.10. The next, as I finish it, will be on building audio plug-ins in LV2 (LADSPA) format, primarily demonstrated with Audacity and LMMS but you can use LV2 in a lot of different things. It's in progress now.
As far as the Debian error goes, this likely relates to Godot. I used an older version in producing Flatland (Godot 3.0), which is fun and small but far from perfect. When I get back to it (need to get the paid products out of the way first), I'll see about the Debian issue and whether it's maintained; there wasn't anything especially unusual going on in the build, but the toolkit was from two versions ago. It's funny, I didn't even realize that it depended on Python.
The new version is Godot 3.2. I'm going to see about testing it on Debian, since that is a freely accessible operating system, and I'm probably going to try and write the game in C instead of GDScript (the default language, an interpreted and veritable syntactual mess that I'm not fond of). In fact, if I'm going that far, I might just build it to WASM and keep a WASI interpreter on hand for each operating system—the game itself isn't that demanding, and it would make compatibility maintenance much easier. One thing at a time.
Sorry you had those issues. Thanks for playing, all the same!