too dark......

agree, much too dark, this would be the ideal situation for fill-flash to balance the image, nice try author

I like the pose and the color, but the focus is just a bit too soft for my taste here

don't see a lot of smiles.

I really like the feeling the reflections in the ceiling give this picture. It slightly confuses the viewing eye for a second before you realize what is actually going on.

As for the mood in the picture, it seems little "dull". The people in the picture seem to be waiting for something that has yet to start, which gives it the "dullness", in my opinion.