From the publisher’s website:
This is it. As its sister game (This Hallowed Ground) did for Gettysburg and (This Terrible Sound) did for Chickamauga, A Fearful Slaughter strives to be the definitive Shiloh game.
Unrivaled in size, scope, accuracy, and development, A Fearful Slaughter is a game on the battle to be savored and played repeatedly. It uses the popular Civil War Brigade Series rules with a set of specially adapted extension rules for Regimental scale action.
The research for the two maps was done using multiple Park histories, battlefield surveys and county historical maps. They show the battlefield in more detail than ever before. They are very graphic intensive.