I love the UI of this app. The colors, highlights, and skins are bright, high contrast and make reading the game grid easy easy.
The levels of difficulty of low, medium, and high are not all that difficult. The game’s challenge, as a result, is more limited in comparison to other Sudoko apps. It would be great if there was another level of difficulty or two.
The hint feature is also rather limited, it offers only a question mark (?) to identify target squares. It would be helpful to have a tiered hint that explains the logic of identifying solutions as a way of building skill over multiple plays.
The app would also benefit from a notes feature so you can record possible numbers by cell in the grid. The recorded notes would be updated automatically based on solved squares.
The game has a nice victory celebration at the end of each win, tiered achievements, and points accumulated toward these achievements that add a fun factor over and above the UI, sound affects, and animations.