I'm so glad I took a chance on Ninja- SBD. I'll definitely by upgrading to the real print cards.
This game is FUN. and fun in a fun way to be fun. Unless you're boring.
One variation I like is to slip a card to someone who doesn't yet realize they're playing. So when they get the news that they've lost, it's like, "Damn. That was Ninja!" (ninja the adjective, I mean.) The only way to improve that would be for the backs of the cards (which have great art!) to have a QR that links to the rules so your victim can see how and why they lost. and thus, the game expands exponentially, like a anti-disease of ninja fun.
But my point is, Get this! Love it! Share it! Love it some more. With every part of your body.