Criticism -
The main mechanic - the less collectibles the "more fast" your speed - didn't come into play too much as most of the puzzles only required you to have one collectible on hand at any time. Introducing more puzzles earlier surrounding having multiple collectibles at a time would have really helped cement the game as part of the theme. Another minor nitpick, the player and the background clouds being the same color made it hard to track the player at times. I would suggest making the player a different color to stand out against the clouds.
Support -
Other than the minor nitpick above, the art style was very pleasing to the eye, and the music fit the casual, calming nature of the game.