To prevent the camera from following the Player when he falls in the game scene,
1. Select the "Camera2D" Node under the "Player" Node.
2. Change the "Bottom" value to 120 in the "Limit" line under the "Inspector" tab. Check the "Smoothed" On box. The value of 120 is the distance from the horizontal center line of the scene to the bottom of the tiles. This value is measured with the "Ruler Mode" button.
When the Player falls down, the camera will no longer follow the Player.