The game is quite hard - but only for player. I think the enemy can attack me succesfully with every single attack, while each of my attack is paused to show the Dice shaking animation to select a random number which is in the corner, so first time you immediately feel like the game just hang and crashed - it's not a great user experience, so reconsider the UI, or just don't stop the fight, even if the rolling system is in the background - you can instead show damage as numbers on enemy etc.
The boss is just getting to you to hit you, so there is nothing sophisticated in it's design. It's an ok game, but it's just a very simple game with nothing unique, except those very long "lags" :D. Some walls have a 3D object that is Z-fighting with the surface.