Looks very cool. Always loved Ruby, but went to other languages for reasons of speed and ... well, lack of the crufty parts.

But...the fact that it's been bootstrapped means that getting it up and running on Windows will be a bit more of a challenge than if it were written in something that can just be built on Windows (C? Go?). I did find this:

https://github.com/manastech/crystal/issues/26

...but the effort seems to have stalled.

Cross-compilation would fix the bootstrapping problem, and is also important for its own sake; for building code that runs on ARM, for instance (for Android, iOS, etc.).

Looks like neither Windows support or cross-compilation have any advocates on the core team, which is sad.