Disclaimer: (We've been crushin on Knizia a bit lately.)
No Mercy!! is a very quick playing push your luck style card game designed by Reiner Knizia.
IMO Reiner Knizia designs are generally known for three things; simple, bare-bones rules, impeccable math, and clever twists.
The rules and setup for No Mercy!! are dead simple and bullet quick to get firing. Of the 40+ Reiner Knizia games we've played over the past several months, this one stands out as possibly having the simplest rules set. I wouldn't magine it taking more than a couple minutes for just about anyone to get playing once they've read the rules.
I expect the math & balance will work at all suggested player counts (2-5) but so far, we have only played at 3. My feeling is that it would be played at it's best at 4 or 5, and it seems a little too swingy for me to get excited about as a 2 player experience.
It is a push your luck game with the highest point total winning. The twist comes in how claimed cards are not scored right away, but are scored at the start of your next turn (before you've performed any other actions) if they weren't stolen during other player's turns and remained in your possession. Having to wait to collect your points while other players chip away at your cards to add to their own reserves keeps you engaged throughout. The way the potential score piles continue to change hands and continue to grow throughout the rounds dulls a bit of the pain. Loosing a juicy score pile doesn't sting as much as you might think because, at least for a while, you have the hope of stealing it back on your next turn.
Overall...a keeper...and I could have played multiple times in the time I spent writing this review...got to go!