Hey Naji,
that was quick And your review si very good. Your feedback is matching with my user tests mostly. Just to give some feedback back:
Missing tutorial: I tested several types of doing that but wasn't able to find a good one. Most users hate to read text and skip it eather or. AS you noticed it is not to hard to figure out how the game works so I decieded to not implement it one so far.
Game modes: It is very interesting that you like those game types more because they r just a side product I will think about it to set it as first/default play mode. The Normal mode with upgrading options is more for experienced users and makes most fun if both player know what they do.
Menu grafics: You are just right, nothing to add. I just focused on the game part.
I will let you know when I am going to upgrade the game. Thanks for taking the time and writing about it
Btw: What is your testing-device?