In order to see the rankings, klick "[4] global rankings" on title screen (or press [4]). You are currently listed as "Guest#90". The rankings can be sorted by different criteria. If you register, the games you played as guest will also be labeled with your username. So you do not have to play a new game.
The replays are a beta feature and not released yet. But I already use them to analyze games and they are also useful to detect cheating.
The game is written in JavaScript on the frontend and uses PHP and MySQL for the backend. In the moment it is only playable in the browser.