First commit

This is the first deployment.

I feel that the difficulty level is just right, not too unreasonable. 

The current issue is that the player's movement speed and the movement speed of obstacles change depending on the frame rate of the playing environment. 

The reason for this is that at the time I was creating this game, I did not know that Time.deltaTime could be used to provide a means of movement that was not affected by the frame rate of the playing environment.