Why is my answer wrong even when the rules are satisfied?
Your submitted answer is wrong.
You need to realize that there are 4 Sudokus and they need to be solved simultaneously. You can't solve just one Sudoku independently. Please check the rules again; if anything is not clear, please ask here.
Thank you for sharing this puzzle with the rest of the world. It was very enjoyable and I think there might be merit in running other fun contests like this.
With no more participants at this time, X-Killer contest is over. Solutions have been appended to puzzle booklet.
Thank you everyone for participating, I was not really expecting 150+ players having a go at the puzzle during weekdays. So David has a point - we should explore possibility of more fun contests.
Congratulations to Kwaka, David, Yuhei for the top 3 positions. While he has come up 2nd few times, this is Kwaka's first win at LMI. David and Yuhei are in the top 3 after a while.