USB Sudoku is described as 'A very small program for playing the original game of Sudoku. Created specifically for use from a USB stick drive. Completely portable. Completely green' and is a Puzzle Game in the games category. There are more than 25 games similar to USB Sudoku for a variety of platforms, including Android, Android Tablet, Windows, iPad and iPhone apps. The best USB Sudoku alternative is LibreSudoku, which is both free and Open Source. Other USB Sudoku like games are Sudoku & Variants, Sudoku Challenge, Gauguin and Open Sudoku.