Thanks! Actually the boss isnt invincible, you can deal damage but the boss doesnt flinch. There are certain ways to interrupt the boss such as waiting for the boss to perform a red aura attack, then if you time your dodge properly you can press the attack button for a counter, which should charge up 1 bar of momentum, with which you can perform a spinning attack by pressing E which stuns the enemy. I actually rushed this game in a week due to committments and wasnt able to make a proper tutorial for the game so sorry about that....the main page of the game contains all the instructions abt the game's mechanics.