Pycopy is a minimalist, lightweight, resource-efficient implementation of Python(-like) language. Pycopy to CPython is a similar thing as Scheme to Common Lisp. Executable sizes of 300-400KB, instant startup, no need to carry around large monolithic library consisting largely of legacy modules - are some but not all of Pycopy's features.
Project page: https://github.com/pfalcon/pycopy
Now has website too: https://pycopy.github.io/
The 3.5 releases implement lightweight import hooking support (forward-compatible with CPython), and contain numerous fixes for previously introduced "strict execution mode" and for general CPython compatibility.
Pycopy's standard library, pycopy-lib https://github.com/pfalcon/pycopy-lib , is also under continued development.
Prebuilt binaries of this release are available at https://github.com/pfalcon/pycopy/releases/tag/v3.5.2
More details about Pycopy -------------------------
Pycopy strives to define a core language features suitable to easily develop efficient programs, while allow for extensibility to a wider set of features for compatibility with existing software.
Pycopy doesn't come with a large builtin module library. Instead, a set of a few core modules are included builtin: inspired, being a noticeable subset, and a little bit of extension, of the corresponding CPython modules. Also, clearly namespaced, to still allow room to implement fully compatible CPython modules. These new modules aren't intended to be an adhoc thing, just an alternative API with a constraint of minimality. Implementation of that API also exists for CPython (WIP), allowing Pycopy -> CPython forward compatibility.
The rest is handled outside the core language, via a separate project, pycopy-lib: https://github.com/pfalcon/pycopy-lib , which strives to port CPython stdlib to Pycopy, while, where needed, provide more lightweight module variants and extensions.
Pycopy is a full-stack project, with ecosystem including a web micro-framework, pure-Python Python parser, FFMPEG bindings, SDL bindings, LLVM bindings, etc.: https://github.com/topics/pycopy