I feel it pretty much holds true when you try to compile any language that was designed without JavaScript in mind into JavaScript, the result is likely to be ugly and/or imperformant. (Not always, e.g. asm.js)

GorillaScript is designed to run with JavaScript semantics and be as efficient as possible (within reason), so that when you write something as simple as `x + y` in GorillaScript, it is efficient, even with unknown types, unlike Python which would need to check `__add__` or Ruby with its operators-as-methods system.

Also, since JavaScript is so different from so many languages with async-by-default, handle through callbacks or promises or something, being able to replicate something as compilicated as Python's GIL in JavaScript would be atrocious as compared to designing your code in a language that nudges you to write "good" JavaScript.