The jellies are worth 18,000 points. Hence, an additional 32,000 points for two stars and an additional 72,000 points for three stars have to be earned through matching of candies.
The blockers will consume a huge amount of moves to clear them.
The board is open with 81 spaces. However, individual special candies except colour bombs are mostly useless if they are not within range of the jellies. Even special candy combinations can be useless if they are not within range of the jellies especially the ones at the corners.
With respect to the two and three star target scores, 15 moves are insufficient to boost the score by a huge amount of points to meet those target scores.