Final Scratch Project - Game Purpose

My game is going to have a frog trying to eat as many bugs as he can. The difficulty of the game will increase because every time someone earns 15 points, the backdrop will change and more bugs will be added with each new level. Level one will start out easy, with only bugs to begin with. Most of my backdrops will take place in a garden/nature setting, as that is where the frog would live. On the last level, there will be a princess which turns the frog into a prince. Originally I had planned to use enemies that would decrease the score if the frog touched it, but I have found that with all the sprites I have already that adding any more would be a little over the top.