On a small screen at first glance the crab looked rather like a disembodied arm and hand, which was certainly confusing. I think that area with the sun, crab and aeroplane is a little cramped and busy. Personally I don't think the crab is necessary, as it adds complexity to the picture without additional meaning and the picture looks good without it.
The bottle gives a nice feeling of being a castaway. I think that HH works particularly well with a sort of weathered finish, like the paint on an old beach hut, making it clear that this is not your usual shiny SF or fantasy, so perhaps some careful muting of the colours might help to blend the different elements of the picture together.