I'm very happy that you enjoy my game and thank you very much for your grateful suggestions. This game project is my final year project for my Master degree and all you have seen is the completed version.
The items you can collect in this game such as coins, stones are generated every 6 seconds and they will disappear 5 seconds later if you don't collect them. You are right, some particle effects will make it more interesting and easy to understand.
I really am interested in playing games so that I chose game development as my Master degree project and I'm a beginner of game development who has lots of technologies and knowledges to learn. Thank you again for your comment. O(∩_∩)O~