What does enabling Scoreloop in Super Hexagon do?

I had to reinstall the game and I enabled ScoreLoop to give it a try.

Now I have a link to "Achievements" in the upper left corner of the main screen. After selecting it you can see the ScoreLoop window, with some (very basic) achievements, leaderboards, your ScoreLoop account (friends, games...), and that's it.

I noticed that enabling ScoreLoop doesn't seem to be retroactive, as I have 0 unlocked achievements, although I have already completed some of the levels. I tried to complete the first level again and still had no effect on the achievements... So I think it's not worth it.

Still, the main reason why I wasn't interested in ScoreLoop is that I wasn't expecting to get a good place in the leaderboards, because this game is hell.