I'm a fan of Deucher's "Real" apps and love Real Sudoku. This app has a similar feel, but has two unfortunate flaws causing me to uninstall it from my iPhone 6S.
First, there is no paid version to get rid of the advertisements. The ads are displayed not just when finishing a game, but during the game.
Second, the app consumes an unacceptable amount of power. When playing the game, my phone gets plenty warm. And in looking at the battery consumption per app for a day, Real Hitori consumed 73% of the juice. I had to connect the phone to a charger twice during the day to address the battery power dropping below 20%.
Real Kakuro does not consume power like this. I suspect the problem is from displaying all those advertisements.