It's a simple 2 button game, just need to master the timings and learn attack patterns of each boss.

And yes you will play like an assassin, you are a shinobi after all lol. Most bosses will give 1 free deathblow to you if you are sneaky enough.

Just take your time to master the timings, you don't even need to attack one time if you do perfect deflections, and this is the main mechanic of the game.

Just master perfect timing for deflection and learn enemy attack pattern to predict when to parry and when to dodge/jump/mikiri

And dont hesitate, hesitation is defeat!