1. Introduction of the game:
The Room: Old Sins is an immersive puzzle game that takes players on a mysterious journey through a haunting dollhouse. As the protagonist, you are tasked with unraveling the secrets hidden within the enigmatic "Null" artifact, which holds the key to solving the puzzles within the dollhouse. With each level, players dive deeper into the unsettling world of The Room, uncovering dark secrets and unlocking hidden chambers.

2. All characters and levels of the game:
The game primarily focuses on the player's journey through the various levels of the dollhouse, which is filled with intricate puzzles and hidden objects. Although the game does not have prominent character development, players engage with a range of characters in the form of ghostly apparitions and mysterious notes, providing a sense of intrigue throughout the gameplay.

3. What attracts users most to the game:
One of the major attractions of The Room: Old Sins is its captivating atmosphere. The beautifully rendered graphics and haunting sound design create an immersive environment that draws players into the game's eerie storyline. Additionally, the intricate and challenging puzzles offer a satisfying brain-teasing experience, keeping players engaged and invested in unravelling the mysteries of the dollhouse.

4. Why it is popular:
The Room: Old Sins has gained popularity due to its unique blend of immersive storytelling and challenging puzzles. The game's cleverly designed puzzles and enticing storyline keep players hooked, making for an addictive gaming experience. The high production value, attention to detail, and atmospheric presentation have also contributed to the game's popularity and critical acclaim.

5. When the game was released and how many versions are currently available:
The Room: Old Sins was released on January 25, 2018, for mobile devices, including both iOS and Android. As of now, there are four versions of The Room game series available: The Room, The Room Two, The Room Three, and The Room: Old Sins.

6. The most difficult part of the game:
The most challenging aspect of The Room: Old Sins lies in deciphering the intricate puzzles scattered throughout the dollhouse. These puzzles often require a keen eye for detail, observation skills, and logical thinking. Players may find themselves spending considerable time manipulating objects, solving riddles, and unraveling complex mechanisms to progress further in the game.

7. Strengths and weaknesses of the game:
One of the strengths of The Room: Old Sins is its immersive atmosphere, achieved through stunning visuals and atmospheric sound design. The game's clever puzzles and intriguing storyline are also major strengths, providing a satisfying and addictive gameplay experience. However, some players may find the difficulty level of the puzzles to be quite challenging, which could potentially be a weakness for those seeking a more casual gaming experience.

8. What other games have been developed by the same developer:
The developer behind The Room: Old Sins, Fireproof Games, has also created previous installments in The Room game series, namely The Room, The Room Two, and The Room Three. These games have gained significant acclaim in the puzzle genre and have collectively established Fireproof Games as a leading developer in immersive puzzle gaming.