Thermo Sudoku

In Cracking The Cryptic’s games, players start with zero stars and earn stars by solving puzzles. The more puzzles you solve, the more stars you earn and the more puzzles you get to play. Only the most dedicated (and cleverest) sudoku players will finish all the puzzles. Of course the difficulty is carefully calibrated to ensure lots of puzzles at every level (from easy through to extreme). Anyone familiar with their YouTube channel will know that Simon and Mark take pride in teaching viewers to be better solvers and, in these games, they always craft the puzzles with the mindset of trying to help solvers improve their skills.