That's pretty amazinf really. The colours and the depth and the construction are amazing so it's a shame to say that it's not a "power" image because you forgot the rule of thirds. I know that's the other challenge but the rule applies to all images that have impact. All this needs is the sun moved onto either the left or right vertical lines. Stuff in the centre for some reason just doesn't work.
7 - Good perspective. In my opinion this would be an even better shot without the sun, the lighting is nice 'around it', but it detracts too much, especially from the clarity of the bubbles.
The composition is very interesting. It almost gives the appearance of a mountain of bubbles. I think the composition would be even stronger if the sun was just above the bubbles such that it gives the appearance that it is rising/setting above/behind this "mountain of bubbles". Not to mention that it would give the appearance that the sun is gently supported/nestled by this tiny delicate bubbles. The other critique I have on this is that there appears to be some sort of object that is slightly out of focus in the top right hand corner. That area of "something being there" distracts from the overall pleasing picture.