That's because Saints in Sin City is interactive fiction - a novel you not only read but also actively participate in.  When you start Saints in Sin City you're not just turning pages - you're stepping into the story as a master spy ordered to stop the terrorist plot with a license to kill and a get-out-of-jail free card in your wallet.

The suspense of not knowing who the enemy is, where they are or what they are planning will haunt you at every step.