The graphics were very pleasant and the sound effects were fun (especially when missing :P). It took me a little bit to realize that the timer didn't continue while you were trying to grab the manatees, but it made trying to get the purple guys more manageable :)
My only issues were I'd like to see my score once the game ended (often was looking only at the timer and didn't know what my score was) as well as all the high scores, and also that trying to move diagonally (or trying to switch quickly between vertical and horizontal) would cause the ship to stop moving entirely which felt frustrating sometimes.