This might not be my preferred game but there are some good points:
1) Great concept delivery of having a very limited time that really pushes the use of the hyper shuriken. I imagine time as a common interpretation of the theme (didn't play much games as time of this writing) but this is a good use of it.
2) I'm going to commentate from the perspective of a beat-em-up/stylish combat enjoyer here: I feel like the hitbox of the hyper shuriken is not that intuitive especially when trying to chain multiple hits. Having to move towards the shuriken moves away some of my expectations going into this.
I imagine if the shuriken slightly moves towards the player, and if it doesn't fly as high vertically (if it arcs lower), and have a more forgiving hitbox (if you are inside the shuriken), it would make it so that the player was able to focus on aiming where the shuriken will go, rather than trying to position themselves better.
Otherwise, great concept delivery, but the actual gameplay itself can be hard to swallow for me.