Apart from the main design goals, Horse64 is made with aspects of the permacomputing movement in mind.
Support for older systems: It's a stated project goal to support both 64bit and 32bit systems, including older versions of Windows and Linux. Sadly, 16bit systems are too hard to make work with some of its features.
Concrete example: the project tries to still support Windows XP, as well as X11 on Linux. No 3d acceleration is required even for Horse64's 3D features. The official UI library has few dependencies and renders in software.
No physically hard to build dependencies: The project tries to avoid dependencies that may be difficult to build, especially on low-end hardware with limited memory. We believe even contributors on old or slow hardware should be able to contribute and to rebuild the tooling.
Conrete example: this is why Horse64's UI doesn't use any web technologies, since web engines are notoriously hard and resource-intensive to build.
Built with low memory ceilings in mind: The compiler was built with manual memory swapping of object file data in mind, so that memory usage can be reduced on low end machines. The main SDK programs are built with a focus on low memory usage.
Avoidance of tech fads: The project tries to only rely on technologies unlikely to go away or to massively change soon.
Conrete example: Horse64 targets simple C89 with C11 atomics and with no aliasing limitations. (C11 atomics are not needed for targets like x64 where 64bit ints are already atomic.) The stack doesn't link any C++ and doesn't need modern C features.
Self-hosted for simplicity: To make the project easier to understand and simpler to reason about, Horse64 is written in itself, using both regular Horse64 and the low-level Horse64 Root.