1. Introduction of the game:
Cultist Simulator is a narrative-driven digital card game that invites players into a world of mystery, arcane rituals, and forbidden knowledge. Developed by Weather Factory, this intriguing title combines elements of strategy, RPG, and roguelike gameplay, where players assume the role of a seeker after unholy mysteries, deciphering cryptic texts, and risking the wrath of the eldritch powers.

2. All characters and levels of the game:
The game does not have traditional characters or levels. Instead, players create their own unique story through the actions they take, influenced by the roles they choose at the beginning, such as the Aspirant, the Physician, or the Detective. Gameplay progresses in a non-linear fashion, with players diving deeper into the occult by gathering followers, performing rituals, and ascending through the ranks of secret societies.

3. What attracts users most to the game:
Cultist Simulator is most attractive for its rich, atmospheric storytelling and the depth of its lore. The game pulls players in with its mysterious world, where every choice can lead to a myriad of unforeseen consequences. It's the immersive narrative and the sense of danger in the unknown that hooks players, combined with the satisfaction of unraveling the game's many secrets and puzzles.

4. Why it is popular:
The game has garnered a dedicated following due to its unique gameplay mechanics, evocative writing, and the way it encourages players to think creatively as they craft their own story. It is popular among those who appreciate games that defy traditional genres and offer a unique, thought-provoking experience.

5. When the game was released and how many versions are currently available:
Cultist Simulator was released on May 31, 2018, and since its release, it has had various updates and expansions, including the "Priest," "Dancer," "Apostle," and "Exile" DLCs. These additions have kept the game fresh and added new content for players to explore.

6. The most difficult part of the game:
One of the most challenging aspects of Cultist Simulator is the steep learning curve and the minimalistic guidance provided. Players are often left to their own devices to figure out the complex systems and symbols, which can be daunting for newcomers. The game also relies heavily on trial-and-error, making the path to mastery a meticulous and sometimes unforgiving journey.

7. Strengths and weaknesses of the game:
A key strength of Cultist Simulator is its deep and engrossing narrative coupled with its unique card-based gameplay, which provides an experience quite unlike any other. However, its weaknesses may include a lack of clear instruction that can lead to frustration for some players, and the slow pace of gameplay may not appeal to those seeking more action-oriented titles.

8. What other games have been developed by the same developer:
Weather Factory, founded by Alexis Kennedy and Lottie Bevan, has also worked on the development of "Book of Hours," which is another narrative strategy game focused on a library of esoteric books. Alexis Kennedy is known for his work on "Fallen London" and "Sunless Sea," both developed by Failbetter Games before the founding of Weather Factory.