The object of all 3 puzzles is to pack the loose pieces into their respective glass containers such that all fit nicely within the glass without "overflowing" the rim. So far I have only assembled and solved the Pineapple Puzzle which appeared the easiest of the three, given the squarish and right-angle shapes of the pineapple pieces. This is a level 8 puzzle according to PuzzleMaster and I think the rating is about right.
The Pineapple has 12 individual separate pieces of which no two are identical and putting them into the glass bottom and working your way up to the top was pretty challenging. It took me well over an hour or so before I finally managed to land the last piece into its correct place. The trick is to get the first couple of bottom layer pieces right, then the rest of the pieces become easier to complete. For those keen on this puzzle; here's a tip-try starting off with the bottom pieces outside of the glass first, to save you dipping your fingers in and out of the glass to change a wrong piece, especially for those with large hands. The glass is small and measures about 2 3/4 inches tall with a diameter also about 2 3/4 inches.
At the time of this writing, I have just started playing with the Plums Puzzle. Although it has 9 fairly large pieces, every single piece is irregularly odd-shaped and all look similar. I am already having difficulties finding the first few right pieces to fit the bottom of the glass...the Peanuts Puzzle looks even more foreboding (rated at level 10) so I guess I will have to save both the Plums and Peanuts reviews for some other time.