Compiling to web assembly should actually be quite easy, given llvm's support. The hard part will be porting the standard library to the environment wasm provides.

We're already well past the point where we could become "native ruby" and I'm glad of that. Ruby has quite a few warts, and I'm glad most of them haven't been copied by crystal.

Compilation times are already well under a minute for the whole of the crystal compiler itself. It was actually improved quite a bit on Linux in the latest crystal release.