The openings are, in part, appear on the sleeve where they should be to me a few holes a little too big, but for me that's ok, that is no reason for criticism. If you like places his phone on display that could not be satisfied here, but I believe that one then has no Lumia 625.
The only complaint:
I personally feel that the operation of the on / off button and the volume on the side is a bit strange, that you really have to push much more strongly. This also has a certain advantage, as I have with the cover off than previous Sony user accidentally before my Lumia. The now no longer happens surely.
Unfortunately, however, has to operate the side buttons neither habituation nor yielding of the material of the sleeve occurred, so I unfortunately here still "a funny feeling button" did. That is why a star deduction.
Conclusion:
For the price you get here is a uniquely useful Protective Cover for Lumia 625 and I think we can strike here without hesitation.