haha no problem, making the video is easier than making a game. The end of sections reward part is a really good idea, going with sonic Inspiration you could combine it with a timer, that way the coins still feel good but also collecting them fast and moving on could be a factor, the end of level time can be converted to more score or what not.
Don't worry to much about the back ground tbh it never got in the way of gameplay. I tend to nitpick great game more since I have many more nice things I could say about the game.