An interesting take on the theme to say the least, it was really fun to just kick all the ninjas, though kinda hard to make them.. I guess kick each other? Otherwise though just moving around attacking and grappling in the same motion was pretty fun.
Overall it had a nice difficulty curve too, though it felt like the box mechanic was sorta... shoved in and then forgotten about? I'm not quite sure.
Also the boss was out of nowhere basically. He can't be grappled to, and he can't be damaged by contact which is really counterintuitive. I would think at least letting him be grappled to would be nice, but instead it ends up being reliant on trying to throw the other ninjas at him, which was kinda hard to pull off to say the least. Feels like it would be more likely for him to just not be stopped and maybe just lose the kunai really fast? Rather than being completely immune.
Especially since the chamber is just long enough that you can't kunai across it.