Bet you can't do this sudoku!

"Though these sudoku might seem like others you've tried, don't be fooled: the clues you get are very different. Sometimes you won't get much information to work with. In other cases, the squares are connected by dotted lines and there's only one sum as a hint. A few sudoku are simply bigger; but bigger means harder, with more numbers to figure out. Plus, you'll find shaped puzzles, arrows, and circles in the middle of the grid, and more." -- Back cover