Nice game in my opinion the best, but there are some notes I would like to make:
first: very nice that you have made several options to play, but the most important is the online one because many people don't want to download the game.
Second: the boss has the sprite a bit bugged
Third: you should keep the game the same throughout the game. I mean you don't have to change the way of life.
Fourth: I don't understand why you made sure that the player has six lives in the boos fight but the boss does only two of damage. Give it three lives and have it do 3 damage.