Have you ever noticed that while 20% of opening moves in Minesweeper would statistically result in a mine, you never, ever die on your first click?
LuckSweeper extends this idea: any time throughout the game when you're forced to make a guess between multiple equally possible configurations of mines, your guess will be lucky!
You still blow up if you uncover any square around an 8, because there's no chance involved there. However, if you uncover any square around a 7, your guess just curiously happens to be exactly the square that was free!
Like the original, LuckSweeper supports right-click to mark and middle-click (in supported browsers) to uncover area. However, middle-clicking may trigger browser scrolling behavior when the page is too large, so you can hide this text and use your browser's zoom feature to fit the board.