(Primary author here)

> Though it seems like the language misses on popular nowadays generators, lambdas and coroutines. So I would say give it a plus on language design, and there is a space to grow.

Lambdas are actually the only way to define functions.

    const f = {args
         /* do stuff */
    }

is just assigning a lambda literal to 'f'. You can also just pass them around, if you want:

    use std
    const main = {
        var value = 42
        thread.spawn({; std.put("hi from a thread. I captured {}", value)})
    }

Coroutines are possible to implement as a library, and generators don't fit well -- there are iterators, though:

     use iter
     const main = {
          var v = [1,2,3,4]
          for p : iter.byperm(v[:], std.numcmp)
                /* use permutation p */
          ;;
      }

> What I think could be done better: compiler infrastructure / FFI.

You can already link to C, but writing the function definitons function definitions are painful. There's ongoing work to take Andrew Chambers' C compiler implementation, and extend it so that it can automatically generate the glue code.

We had a Summer of Cod[1] person working on it, but they dropped out due to lack of time.

[1] https://myrlang.org/summer-of-cod