Very Very interesting game !! it was a really smooth experience, here is my feedback:
-The Game design is really smooth and eye-pleasing
-The particle System was also really great
-The music is also decent and really suitable to the theme and the game style
-I Really like the idea of implementing Puzzle challenges with a negative effect ,It was a really cool idea and it added much to the game.
-I noticed that in the main menu the cursor is actually underneath the UI buttons, so take a look at the Z-ordering
-I also noticed that when the player dies, he restarts in the same level but the issue here is that the killed enemies doesn't spawn back, which to be honest makes the game a little less challenging with no punishment for dying, so a player can just rush kill an enemy without caring if he dies.
overall it was a really cool experience, Looking forward for future updates !!