I Think it is fine , the idea , the concept is Fine . The way it looks if fine too, but the way it is implemented maybe could be different/better .
This screen every time you get a level 4 ender could be too much. Some people ( really good ki players and relevant members os the FGC) had said that it affects important aspects of the game, I think that this level 4 ender animation should be only displayed in certain situations and not every time you reach a level 4 ender .
For example .
instead of every level four ender , use it on level 5 enders or when a level 4 ender comes after a shadow linker .
Also when a level 4 ender takes all the remainng life bar this could be cool with a slow motion effect on the ender until the enemy hits the floor , no matter if it is first or second life bar.
I like the idea, but the way it is implemented i think is too repetitive.