Director M.J. Bassett and the film's producers intended to make two further Solomon Kane movies to complete a planned trilogy, one set primarily in Africa and the other at least partially in colonial North America.
When Kane says that he sailed with Admiral Drake, he's referring to the poem "The One Black Stain" by creator Robert E. Howard. In the poem Kane speaks out against Drake's execution of Sir Thomas Doughty in 1578 Patagonia, South America, hence why Kane says "That didn't end well."
Director M.J. Bassett cast Max von Sydow as Kane's father because he believed that if this film was made in the 60s or 70s, Von Sydow would have been perfect for the part of Solomon Kane. Von Sydow's film The Seventh Seal (1957) (1957) was also a minor inspiration for this film.
The second movie adaptation of a Robert E. Howard character to feature Max von Sydow - the other being his role as King Osric in Conan the Barbarian (1982). Interestingly in both movies he plays the father of a child who is in thrall to the movie's main villain.