A very simple puzzle game in terms of the premise, but a simple premise does not mean that the solutions are simple. The combination of arithmetic and Sudoku is fascinating and works marvelously. This game really had the gears turning in my head. I also love just how relaxing this is, and it is never too frustrating either. I'm glad that this is a demo because that means that there will be more, and I simply cannot wait to solve more puzzles. This is a game that I will definitely come back to in the future whenever I need to wind down and relax.