Castle Itter is a solitaire design with 2-player competitive or cooperative options that sees the SS units activated by cards and then advance on the Defender’s positions inside the castle along various tracks. The defender must simply last till the deck expires and move units around the board to various positions and eliminate units before they enter the castle.
I have written several posts on this one in the form of Action Points. Here are links to those 4 posts:
We also posted an interview we published with the designer David Thompson on the blog during the Kickstarter campaign: https://www.google.com/amp/s/theplayersaid.com/2018/11/05/interview-with-david-thompson-designer-of-castle-itter-the-strangest-battle-of-world-war-ii-from-dan-verssen-games-coming-soon-to-kickstarter/amp/