For anyone who already owns the game, there is a new ZIP file available at its itch.io page. There is also a more limited demo version of the source code available for free, alongside the free demo.
I am releasing this code with the Creative Commons Attribution License, so that others can be free to reuse it, even in commercial works. Only the source code is licensed this way, however. All of the game content, levels, graphics, music etc. is excluded from that license.
I've placed the demo source on GitHub as well, mostly for the convenience that provides:
The source package also includes a Windows build of the Lizard Tool, so even without being able to program you can still poke around in the level editor and see how things were put together.
If you find a use for this stuff please tell me about it!