Clans at War: Black vs. White is a stealth/action arena platformer. It tells a story about the never-ending war between the clan of ninjas and the clan of scary ghosts with torches (yup).
The main thing is, you can't see a black character on black background - or white on white background! It's hard but satisfying, unusual - but you can get used to it. 
Stealth, duels, maps with their own unique gimmicks that may change your overall strategy - it's all here. And all in beautiful black-and-white pixel-art!