Where is the code review UI?

I seem to be unable to find the review interface on CheckIO. Unless the textual comment below solution code is what's meant by "review"... I was expecting something Gerrit or Crucible like, where I click into a line of code and give specific feedback. Is this possible at all? Or will this option become available only after I reach a certain level on CheckIO? Am I just blind?

I have seen other user ask this question as well, but they did not get satisfying answerw from my point of view.

Thanks a lot.