The idea for your plugin is really excellent. However, there are several areas for improvement. Many people use plugins that already modify the chat in normal times and it is necessary that you add for example placeholders that can be used in our plugin which manages the chat.
Also I wanted to add that a better description would be needed. We don't know at all how we gain levels. Game time? Game actions? ..
Obviously, this is not to be taken badly, there is a beginning to everything!