Generating a game board with squares in a rectangle
directions as a variable name instead of directionTuples.  
Instead of having a bunch of ifs in generateBoard, use pattern matching.
Instead of passing x: Int, y: Int in generateBoard, just pass a tuple which you could call currentPos.  You could define a function to add the direction tuple with the currentPos tuple instead of typing x + directionTuples(direction)._1, y + directionTuples(direction)._2 twice.  (There might actually be a very easy way to add (Int, Int) + (Int, Int) in Scala, but I can't think of it right now.)