I've just updated the release version (see link in OP for "compiled version"). It now comes in a ZIP file. You are supposed to copy the contents into a folder "test" (sorry, still didn't manage to come up with a clever storage point...) in your document partition. Except for the contents of the "launchpad" subfolder, which you can copy into the launchpad config folder on your document partition if you want to use this integration.
The software now has Gamma adjustment (volume keys), beginnings of flexible Zoom including fit-to-content and now stores last read page and last used gamma for each document viewed. Oh, well, and it comes with a simple file chooser now.
I think it's coming towards a point where the main development will focus on the Lua scripts and the C code part is almost stable (although still not complete, things like metadata or text extraction are still missing). I still like the lightweight approach, and it's reasonable fast to script a UI in Lua. I've added access points to font rendering as freetype is included anyway (and some fonts are also always there).
It might also be a base for scripters who look for a base that can interface with the framebuffer, the input and also brings sqlite. Lots of little apps come to my mind. So if you like Lua scripting, this might be for you, even if you don't use it to read PDFs.