Robert D. Anderson & the Legacy of Cthulhu is a fan made project based upon the Arkham Cycle Cthulhu stories by H.P. Lovecraft. More specifically, it is an adaptation of the pen & paper scenario Himmlers Schoggothe by Samuel Miller. The game is best described as a horror novel, using three means of storytelling: spoken word, filmed cut-scenes and playable content from a first-person perspective, built with the FPS Creator engine.
The player is cast as the hard-boiled private investigator Robert D. Anderson from New York. That is just a pseudonym however to hide his real name, Robert Dietrich. After an incident, he is forced to investigate his origins and travel to The Third Reich where the castle of his ancestors is occupied by SS troops and members of the Order of the Black Sun.
The game is divided into 15 chapters. In the playable sections players must explore the castle, talk to characters, solve puzzles and defeat enemies - combining shooter with adventure gameplay. Up to 20 weapons and spells can be collected, but it is encouraged to avoid confrontations.