This project is super cool, but I'm even more hopeful for Rust eventually being a much more complete replacement for C++ and even C for embedded projects. It's already pretty easy to run outside the runtime by not using the standard library[0], though you can't take advantage of a lot of Rust's niceties if you do so. There's discussion of what it might mean to have the standard library but not the runtime[1], which could be really nice for embedded projects.