Good start
But needs a bit of refining.
Yah, you need to figure out the "snap to grid" thing, though I would advise against it during gameplay. When you figure it out, maybe have the "snap" as a button you hit when you solve the puzzle. Not having them snap makes the puzzles much more challenging to solve, because if you're out a littl bit on each piece, eventually, nothing seems to line up. (And I actually like that, it adds a layer of challenge).
The othe (minor) beef I had was you need to work on having a better contrast for your backgrounds. I found it a bit eyestraining to figure out what was background and what was a piece for some of them, especially on the on the hard "Pirates" puzzle.
Beat all the puzzles.