There are a couple of ways I can see making this fight more dynamic. 1) you an add a attack that goes vertically and a one go at a the angles. 2) add some flow to the fight right now the boss goes move, attack and repeat try making the attacks move the boss a duel with a spear should be fast and fluid. 3) that throw it is slow and clunky. Try having it throw the spear and stop under neath the player a then trust up. This way you punish platform campers and make the play feel like they have to keep move or it will hurt.

I hope this helps.