Thank you a lot for so much feedback! This really helps a lot.
I definitely agree about the grades in tutorial levels. I got used to playing those levels so much that it is getting exponentially harder to estimate what a proper rank time should be. Lucky I recently introduced leaderboards so I can use some real players times to see what ranks to use.
And about attack animations of enemies I plan to have more variety of enemies in later zones with unique attack patters. In the first zone I kind of have simple "move towards" type of enemies for players to learn positioning around them as much as possible.
I will go check out your game now!