The menu Game menu lets you control the status of the current game, as there are:
Undo the last step. Same as the back button in the Toolbar.
Redo the last step. Same as the forward button in the toolbar.
Show a tip, which two tiles to remove next.
Finish the actual game set and start a new session with new tiles.
Restart the current game with the same tiles.
Pauses the entire game, especially the timer which is needed for the high score. The menu-entry then turns to Resume Game, which is used for resuming the game.
Shows a Dialog which tells you whether the game is solvable or not. If the menu-entry Disallow unsolvable games in the Options menu is checked, this Box is absolutely useless.
Shows the (local) Top-Ten-charts of Shisen-Sho.
Some of the menu items can also be controlled by hot-keys. See the section for a list.