When working with sprites, you'll probably not want to rotate the game object. For sprites, you have to manage this through animations or (if it's a side scroller) through negating the scale.
An example for side scroll handling can be found in the 2D Platformer tutorial series - check out the Flip schematic found here.
For top-down, it's a bit more complex - you'll have to determine the direction from the player's input (up-down, left-right) and play the according walking animation.