Fun concept with some breaking flaws.
So, I'm a picross fan. Any new spin on it like this invariably excites me. It did some things right - smooth visuals, the addition of color makes the images a lot more fun to chip out and adds an interesting new level of challenge. Locking onto one row or column when the cursor is dragged down one is a -godsend- and I wish more of these games did it.
Onto the hard stuff: The font you use for the numbers is a pain to read, especially on lowest magnification or lighter colors against the light background. Speaking of magnification, I don't like this system. I don't like it at all. Not being able to see what I'm working on is disorienting and the larger puzzles are simply not possible to fit on the screen, even at lowest magnification (where I can't tell a 6 from an 8 from a 9 in your font). The way the icon to move the image is situated on the bottom of the screen also makes it a pain to drag downward in the small margin left below it. Dragging the pen down a row or column, much as I love your system there, can be buggy and leave gaps if you're not cautious. The numbers along the edges also occasionally don't fade out where they should - several times I had to erase and fill in a block again to get them to work. The puzzles themselves are mostly good, but in several cases a combination of very few large blocks of any single color and excessive use of blank space in the art made them next to impossible to solve without simply guessing. I actually suspect the puzzles "I can hear the sea," "violet lilies" and "curious dragon" are literally impossible to do on paper without a computer confirming if your guesses are right or not. Several other puzzles had certain moments like this (furred bandit, hiding in the bushes), but they were mostly mild enough to solve with the single hint you get from the coin. That's a nice feature, by the way, I wish the tutorial had told me about it. I didn't know it was there until I stumbled into it much later in the game.
Six is the highest score I grant where design flaws go far enough to interfere with my enjoyment of the game. It's an otherwise very good game so I'll be merciful; 6/10.