Wolf Munroe ☎Shinobi: Art of Vengeance is half off (so $14.99 USD) right now on Steam.
I snagged it.
I started a game and was presented with options of "Normal" and "Hardcore" difficulties. I chose Hardcore. After playing 4 hours, I restarted on Normal. I am at the second boss on Hardcore difficulty and just moving into the third level on Normal. It appears "Hardcore" was just added to the game last month.
I will probably continue to play both.