Hello.
I calculated and currently your life span should be 9 attacks from the boss on average. To take down the boss 5 tries on average are sufficient.
This does not even take into account hidden skill stat meaning the odds are even better. I think I will slightly change damage dealt by the boss, but I can't make it easier to the point where doing random things will kill the boss. If you understand the pattern, boss will be quite easy (I will add a clue in next version)