1. Introduction of the game:
Mobile Legends: Bang Bang, often abbreviated as ML or MLBB, is a mobile multiplayer online battle arena (MOBA) game that has captured the hearts of millions of players around the globe. Developed and published by Moonton, the game offers fast-paced and strategic 5v5 player versus player action. Each match takes place on a well-designed map featuring three lanes, a jungle area filled with neutral monsters, turrets defending the paths, and bases that players must conquer to win.

2. All characters and levels of the game:
Mobile Legends boasts a vast array of characters, known as Heroes, each with unique abilities, roles, and backstories. The roles include Marksman, Assassin, Mage, Support, Fighter, and Tank. Heroes are diversified across these categories allowing players to choose their preferred playstyle. Additionally, the game has several levels of progression for each character, where players can unlock new abilities and strengthen their Heroes by leveling up in each match.

3. What attracts users most to the game:
Players are most attracted to Mobile Legends due to its competitive gameplay, quick matchmaking, and the strategic depth provided by the variety of Heroes and team compositions. The game's social elements, such as forming squads with friends, and its mobile-centric design allowing gamers to enjoy a complex MOBA experience on the go, add to its appeal.

4. Why it is popular:
Mobile Legends is popular because of its accessibility, with matches that are shorter than typical PC MOBA games, making it appealing for playing in short bursts. Its ease of entry for beginners, coupled with the depth of strategy for experienced players, and a constant introduction of new Heroes and events, keeps the game fresh and engaging.

5. The most difficult part of the game:
One of the most challenging aspects of the game involves mastering the high-skill cap Heroes and effectively executing complex strategies during high-stakes matches, especially at competitive ranks. Coordination with the team and adapting to dynamic in-game situations provides a steep learning curve that can be demanding for players.

6. Strengths and weaknesses of the game:
Strengths of Mobile Legends include its easy-to-learn mechanics, quick matchmaking, and a large and active player base. It runs well on a variety of mobile devices and has an engaging reward system. Its weaknesses could be viewed in terms of hero balance – some Heroes are perceived to be more potent than others, resulting in a sometimes uneven competitive experience. Additionally, like many online games, player experience can sometimes be marred by teammates with poor sportsmanship or connection issues.

7. What other games have been developed by the same developer:
Moonton, the developer behind Mobile Legends, has also worked on other titles such as Mobile Legends: Adventure, a role-playing game that offers a different genre but set in the same universe. The company has been focusing on expanding the Mobile Legends franchise but also explores other gaming genres and experiences for its audience.