When I hit the play button, the game screen shown is a larger area than what my camera is supposed to show (according to the rectangle). How do I only show what is in the camera's rectangle?

When I click on my camera it shows a rectangle that I assume is the area it covers in my 2d game. But when I hit play, its showing me more than what is in that rectangle. How can I fix that? I only want what is within that rectangle to be shown to the player.

Try changing FreeAspect to constant aspect in the “Game” window:
181778-aspectratio.png