Yes. Duskrow runs free in any modern browser on desktop, tablet or phone, with no download, no install and no account. There is one puzzle a day and it costs nothing to play.

Choose one of the three shapes at the bottom, then tap a window. Every window that shape covers flips: lit ones go dark and dark ones light up. Keep going until no window is burning. Tapping the same place with the same shape undoes it exactly, and there is an Undo button as well.

Because a tap flips everything the shape touches, not just the window you aimed at. That is the puzzle. The route to a dark street is a set of stamps whose unwanted flips cancel each other out, so it is usually shorter to think about which stamps overlap than to chase individual windows.

Par is the shortest route the game could find on that board, computed by searching move combinations before the puzzle is served. It is a real minimum rather than a designer’s guess, so matching it means you found the best line. Beating it is possible when the search does not look deep enough, and it is recorded as under par.

No. Each night is generated by stamping shapes onto an empty street, and every stamp is its own undo, so the same stamps always put it back out. Solvability is built into how the puzzle is made rather than checked afterwards.

Solving today’s row once adds one to your streak; missing a day resets it. Solving the same day twice does not count twice. Older rows are available as practice and are deliberately kept out of the streak, so you cannot farm thirty days in one sitting.

Somebody is still in that room. Those windows stay lit, they are not part of the goal, and no shape can flip them — but shapes that overlap them still work, they just affect one fewer window. Reading which of your stamps are being quietly weakened is usually how a hard night gets solved.