Haha. Yeah, can't really say why... but I just love adding those little error/details... To me, the most common mistake in digital painting is over detailing, smudging... making everything so perfect it loses all sense of life and spontaneity. Now... I do understand that adding "splatters" and "errors" has nothing to do with spontaneity, but hey... I like just the look it gives...
To ME, everything in this is just grate and very well executed. And i think you are correct about the splatters and imperfection. (You need more splatters).
The only thing that bothers ME is the shadow. its not mixing well with the art. its too smooth, clean. and also fades instantly at the end.
Red circle: Too smooth and clean.
Blue circle: That imperfection and rough edges on the shadow matches with the overall design, and that part is a good example of how the shadow should be.
just an opinion, Otherwise grate work.
Edit: its disappointing that we dont get to see that 'girl in monokini'.