1. Introduction of the Game:
"Sword Art Online Alicization Rising Steel," also known as "SAO Alicization Blading" in Japan, is a mobile role-playing game (RPG) that immerses players in the intricate universe of "Sword Art Online," particularly the "Alicization" arc. Combining a mix of anime-style narrative, turn-based battles, and character progression, the game allows fans to re-experience the story of Kirito, Eugeo, Alice, and other memorable characters from the series.

2. All Characters and Levels of the Game:
Players can collect and level up a diverse cast of characters from the "Sword Art Online" series, including fan favorites like Kirito, Asuna, and Sinon, alongside new faces exclusive to the "Alicization" storyline such as Eugeo and Alice. Each character can be upgraded for enhanced abilities and performance in battle. The characters are divided into different rarity tiers, with higher tiers being stronger and more versatile in battle. Levels in the game typically follow the narrative of the anime, leading players through various challenges and zones reflective of the "Alicization" world.

3. What Attracts Users Most to the Game:
The main attractions of the game are its faithful recreation of the "SAO" universe, the strategic combat system, the stunning anime-inspired graphics, and the opportunity to create a personalized team of beloved characters. Players engage in high-fidelity combat scenes, complete with impressive animations and special moves that capture the essence of the anime.

4. Why It Is Popular:
The popularity of "Sword Art Online Alicization Rising Steel" stems from its strong association with the popular "Sword Art Online" anime and light novels. It appeals to both fans of the franchise and newcomers who enjoy immersive storytelling and strategic RPGs. The game's popularity is boosted by regular updates, in-game events, and the appeal of collecting and upgrading an extensive roster of characters.

5. When the Game Was Released and How Many Versions Are Currently Available:
"Sword Art Online Alicization Rising Steel" was released in 2019. As the game is updated frequently with new content and events, it generally follows a versioning system tied to these updates rather than significant standalone versions. The exact number of versions may vary depending on the latest updates and patches provided by the developer.

6. The Most Difficult Part of the Game:
The difficulty often spikes in the high-level content such as challenging event quests, multi-player raids, or the competitive PvP modes where strategic team composition, proper gear, and timing of abilities are critical for success. Moreover, limited-time events often feature enemies with unique mechanics that can be tough to overcome without a well-prepared team.

7. Strengths and Weaknesses of the Game:
Strengths of "Sword Art Online Alicization Rising Steel" include its rich, story-driven content, appealing graphics, engaging battle mechanics, and its strong community of fans. On the downside, some players may find the gacha system for obtaining new characters to be an obstacle, potentially leading to frustration for those who prefer not to spend money on in-game purchases. Additionally, the complexity and variety of systems for character progression may be overwhelming for new players.

8. What Other Games Have Been Developed by the Same Developer:
The game was developed by Bandai Namco Entertainment, a prolific game developer and publisher known for numerous popular titles. They have developed several other games within the "Sword Art Online" franchise, such as "Sword Art Online: Memory Defrag" and "Sword Art Online: Integral Factor," along with many other games across various franchises, including "Dragon Ball Z: Dokkan Battle," "Naruto Shippuden: Ultimate Ninja Blazing," and the "Tales of" series.