MbraneMbrane is an area control game, played with placement restricted
according to the standard rules of sudoku. Each number can occur
at most once in each row, column, and 3x3 subregion of the board.
Control is determined by the difference of values placed by red
and black in each region, and by 1/2 the value of squares adjacent to
the region, and by a chained resoltion rule starting with the region
with the greatest difference. You can see a worked example with
this explanation of the rules.
There are nice (and free) Android and IOS apps for Mbrane, and Mbrane can also be played by Steve Taverner's AI-AI
Due to the somewhat fiddly resolution rules, Mbrane is best played with the assistance of a computer; but many boards
intended for solitaire sudoku puzzles have red-black tiles, and by treating the "9" tiles are 0, you can play on a real board.
The bots are pretty good, but not unbeatable.