This is as far as I got with a sudoku in Simple Sudoku
..3|...|...
7..|98.|.16
.1.|.73|...
-----------
3.4|8..|9..
19.|...|.58
..8|..6|4.1
-----------
...|34.|.2.
24.|.19|..3
...|...|7..
..3|1..|...
752|984|316
.1.|.73|...
-----------
3.4|851|9..
19.|43.|.58
5.8|.96|431
-----------
...|34.|12.
24.|.19|..3
.31|...|7..
[49] [68] [3] [1] [26] [25] [258] [479] [479]
[7] [5] [2] [9] [8] [4] [3] [1] [6]
[4689] [1] [69] [256] [7] [3] [258] [489] [2459]
[3] [26] [4] [8] [5] [1] [9] [67] [27]
[1] [9] [67] [4] [3] [27] [26] [5] [8]
[5] [27] [8] [27] [9] [6] [4] [3] [1]
[689] [678] [5679] [3] [4] [578] [1] [2] [59]
[2] [4] [57] [567] [1] [9] [568] [68] [3]
[89] [3] [1] [256] [26] [258] [7] [469] [459]
Now the hint it gives are about Colors. I don't understand it, could anyone explain it?