First: Great work!!!!! Second: I have struggle to use the Assets. Like the Progressbar is just a square but I need ist longer and fills. But what can I use? When I stretch the PNG then it looks weird.
For that case, you usually tile the texture. The basic idea is to draw the left part of the progress bar, then repeat the middle part until the desired length is reached and then draw the right part. What engine/framework do you use?