I like this! Seeing the possible numbers listed (and being able to simply click them in the square itself) eliminates a lot of the tedious bits of regular Sudoku.
My one gripe is that the inconsistent line thickness of the big 9x9 boxes combined with the fairly chunky borders on the single cells makes it a little hard to tell at a glance where those 9x9s start and end. But I saw the note about updating the art style so I can't be too hard on it!