Here is an overview of the game, via its Steam page:
Shinobi alert! Use your seven shinobi weapons to survive the bloodshed! Introducing a hard core 2D ninja action game by hyper-retro graphics.
Shinobi non Grata is a 2D platform game where you play as Kaina, a descendant of the Fuuma shinobi clan, and fight against the Oboro Ittou clan who is scheming to overthrow the government by teaming up with demons.
Cut down your foes using your trusty sword Murasame! When you’re in a pinch, use your Shuriken, Kusarigama and Elekiter! Fight your way through an abandoned shrine, a valley of ghosts, a ninja mansion and defeat the boss in the end.
It is 1838, the 9th year of the Tenpou era—a time of turmoil in Japan.
Genba Kisaragi, leader of the Oboro Ittou clan forms an alliance with demons with the objective of overthrowing the bakufu government.
Only one dares stand before them; Kaina, the descendent of a bloodline of shinobi specialized in fighting demons.
This is where his battle begins.
Watch the announcement trailer below. View the first screenshots at the gallery.