This is nice! Readers may also enjoy Simon Tatham's puzzle collection, available for mobile as well: https://www.chiark.greenend.org.uk/~sgtatham/puzzles/ (My favorite currently is Dominosa. Playing the Hard mode is teaching me new patterns.)
(I'm stuck on Guess aka Mastermind right now, and damn good at it if I say so myself! Also Solo aka Sudoku on 6 sub-blocks, with X+Jigsaw+Killer & No symmetry+Unreasonable difficulty.)