It is ok, I guess, but the main downside of this kind of puzzle is that you can not plan the whole movement in advance to moving because you do not know which collectible will be third, 4th etc., because only the 1st and 2nd collectible differ from the remaining ones.
but keep at it, maybe you will find a nice way to give all collectibles a pattern that makes visible in which order they have to be collected! Maybe combine small-to-large pictures with pulsing animations?