Sudoku (Number Place) application. This app generates unique sudoku puzzles in 4 levels of difficulty (thus the name SUDOku + uniQUE) and provides a client with an intuitive interface.
This sudoku application supports two input modes - Digit First and Cell First.
Each sudoku puzzle is auto-saved every time you leave the client and can be resumed later. There are unlimited undo/redo's persisted along with each sudoku puzzle, so nothing is lost.
Keypad has helpful info on keys (block presence, number counters).
There are helpers available if you get stuck on a sudoku puzzle (auto pencilmarks, auto solve).