I have been using crystal+ vanilla js for my pet project and the sheer joy i get from using this language is something else.
2019 has been a good year for crystal. Basic multithreading is in. Windows support is making good headway. I am optimistic that a working windows compiler would be out by end of year.
The last major dragon for crystal to slay would be the compilation time. It still feels unreasonably high. Hopefully that would be a major focus of 2020