Yes, although only for a toy project. I'm sure it'd work fine with Cygwin or WSL, it might work with MSYS, but I've definitely had it working with busybox-w32.
> Is a build directory just a habit from using Make or is it a flaw of redo to not support that well?
You can use redo in a Make-like fashion by putting a single `default.do` in the root of your project that decides what to do by examining the filename it's been asked to build. That does give up some of the benefits of redo, however (since a single file builds everything, when you edit that file redo wants to rebuild everything).
Having a separate build directory that can be easily wiped is a good idea, but I'm a lot less worried about it (or things like 'make clean') now that I have 'git clean -dxf'.