Puzzles

Sudoku is the classic number puzzle, built here to be accessible to everyone, so there is a colourblind-safe mode that swaps digits for colours. It is the starting point for this group, and the other three give you something new to chew on.

Sudomine mixes Sudoku-style line counts with Minesweeper-style neighbour counts on a small grid. Every board is solvable by deduction, so you never have to guess, and one tap is the whole control scheme. It comes in three sizes, from 5x5 to 7x7.

Strata takes Picross into three dimensions, themed as mineralogy. You chisel rock away from a block to free the crystal inside, guided by clue plates on every line. All the clues are visible from the first move, and a solver checks each dig so it can be cracked by reading alone. You can work through it slice by slice in a layer grid or turn the whole block in 3D.

SCADA of Mystery is the odd one out, and I have kept it in this group because the puzzle is the world rather than a grid. It is a roguelike set in a copper concentrator that its own optimisation routine has taken over. You are the on-call engineer, moving through seven zones of an ASCII plant with your tools and your wits. It suits people who like working out how a system fails more than filling in a board.

Sudoku, Sudomine and Strata save automatically, keep their own best scores, and install as apps for offline play. They run on phones as well as desktops. Start with Sudoku if you want something familiar, Sudomine if you want a faster puzzle with a twist, and Strata if you want something slower and more spatial.