You have a working playground and have briefly released a binary. At the very least the second qualifies as a distribution, an important event when we are talking about F/OSS. Your language is therefore still proprietary.

Many current programmers think F/OSS as a norm and proprietary (released or not) as exceptionally shady. Even though some may think proprietary software is acceptable, something being F/OSS is a label with the non-trivial amount of value. Your act can be interpreted as claiming that value without actually being F/OSS, no matter what was your intention.

Honestly, what is the holdup on releasing the source? Other languages are developed entirely out in the open - what are you worried about? Why not just release it today in whatever state it's in, as was previously promised?

Without releasing it you're expecting people to put blind faith in you.