Thanks for your feedback!
I agree enemies are fairly similiar in first 3 zones, but there is more variation in enemies in later levels.
Im not sure about tutorial level, but i could perhaps add some hints when playing for first time.
I think you got somewhat unlucky with fruit drops :D Your lives are restored when you get to shop level. (Unless you are playing on hard mode)
Changing crosshair color is pretty cool idea. I will consider it :)