Nonogram — free browser game

The numbers above each column and beside each row tell you the lengths of consecutive runs of filled cells in that line. '2 1' means a run of 2 filled cells, then at least one gap, then a run of 1 filled cell. Left-click a cell to try to fill it: if the solution wants that cell filled it stays green, otherwise it flashes red, becomes an 'X' mark, and you lose one life. Right-click (or long-press on mobile) marks a cell as definitely empty — purely a personal note, no life cost. Win by filling every solution cell. After 3 mistakes the game ends; your score is the number of puzzles solved up to that point. Press R to restart the current puzzle and N to give up and skip to a new one (the skipped puzzle doesn't count). Strategy: solve lines where the clue sum is equal or close to the line length first — those have forced filled cells; then cross-propagate the eliminated cells to other lines.