Opdoku = Calcudoku + Mathdoku

I love the variety of modes in this game. The UI is clean, easy, and fast to use. I like to play some of the hardest modes. It forced me to think outside the box. Old request: I would like to have a way to mark possibilities on each tile as opposed to only one number. EDITED: They were nice enough to add this feature, yay! Ongoing request: I also want to be able to momentarily highlight all numbers of a specific value on the board (both big and small numbers) to make it easier to see what to do next. This will be especially useful for harder puzzles.

There are no advertisements, they’re not hounding you for money, and the implementation of the puzzles is great. It’s a breath of fresh air.

Very fun.