Everything runs in this browser tab. Your settings and puzzles never leave your computer.
One puzzle per page, page shaped to the screen. Tap a number in the contents to open a puzzle, tap Solution to check it, tap back to return. For selling or using as a PDF; KDP does not take tap-through books.
Killer Sudoku stops at Hard and Star Battle has Medium and Hard; they use their nearest level.
Same code and settings make the same book again, for a reprint or a fix. A new code makes new puzzles.
The free sample has 12 puzzles and a SAMPLE watermark, so you can check the pages before you subscribe.
Gridbinder