Looks great, so far.
If you're worried about the transparent text bubbles, maybe just outline the white lettering with black or 75% gray.
My major concern is that webcomics should be visible entirely on one screen. And I have a pretty big monitor (1600x1200 resolution), so I know some folks must be scrolling forever to get to the bottom.
Also, the simple backgrounds will look marginally better if you down-size the frames a bit.
Not that it isn't neat to get full resolution comics. But it's not the best web-presentation strategy.
But, as you'll have noticed, I have no complaints about the drawing, composition, coloring, or story-telling.
So well done on that front.