@PPK: That icon is really looking good.
I guess that's some special skill, finding two pictures, merging parts of them and still having the result looking that good although there wasn't that much time spent creating it (in comparison to your other stuff).
@km: I already liked how the achievements were displayed in Beta 3, I think a lock icon in the lower right corner would take away a bit of the GE: S feeling. (or you could as well say it's just because I don't like the idea of the lock icon present on the picture, which reminds me of the L4D achievement style, which I don't like either)