Nice game !
The art and enviroment feels great with the camera position and the audio is good too. The gameplay is fun and challenging with the boss fight.
Obviously needs some polishing, for example a timer as the one in the boss area for each time you enter an area with enemies and invisible walls to make you kill all the enemies before going to the next area: Thats cause now you can ignore evey enemy and go into the boss and also feels weird not having life bar for your character in the previous sections of the boss, so my suggestions would help with that. I suggest you fix the fact that you can walk over enemies and a great thing to make the game feel more polished (altough very optional) its making enviroment items such as barrels impassable but destructible when hit. Last thing i would say is that the player already knows the controls when he reaches the boss, so i would remove the control icons in the screen during the boss figth, so there is only the relevant info (as you already know controls). All in all, you made a very solid game, congrats !
Also, you can try my game if you want, it just takes 5 minutes ;)