1. Introduction of the game:
FarmVille 2 is a highly engaging farming simulation game developed and published by Zynga. As the sequel to the original FarmVille, it transports players to a beautifully rendered 3D countryside where they can cultivate crops, raise animals, and build their dream farm. Enhanced with new graphics and gameplay mechanics, FarmVille 2 offers a refreshing and immersive rural experience that continues to captivate gamers across the world.

2. All characters and levels of the game:
Players encounter a diverse cast of characters, each with distinct personalities and roles. These characters include farmhands that assist with tasks and other villagers who provide quests and farming advice. As for levels, FarmVille 2 does not follow a traditional leveling structure. Instead, players progress by expanding their farm, unlocking new areas, crops, animals, and buildings as they earn experience points and level up.

3. What attracts users most to the game:
Users are drawn to FarmVille 2's charming aesthetics, the satisfaction of watching their farms flourish, and the relaxation provided by the game's pacing. The social aspect also entices players; they can visit friends' farms, trade goods, and help each other with tasks.

4. Why it is popular:
FarmVille 2's popularity can be attributed to its accessible gameplay that appeals to a broad audience, its social interaction features, and the rewarding growth system that mirrors real-life farming but without the grueling physical work. Its fun and family-friendly nature has captured the hearts of millions.

5. When the game was released and how many versions are currently available:
FarmVille 2 was released on September 5, 2012. Since then, multiple versions have been introduced, including FarmVille 2: Country Escape for mobile devices and FarmVille 2: Tropic Escape. Today, players can enjoy these iterations across various platforms, each providing unique settings and features.

6. The most difficult part of the game:
Players often find that maintaining the farm's economy and managing resources can be challenging. As the farm expands, strategic planning is required to balance crop production, animal care, and the construction of new buildings to maximize efficiency and profit.

7. Strengths and weaknesses of the game:
Strengths of FarmVille 2 lie in its graphics, user-friendly interface, and the addictive nature of farm management. However, its weaknesses include a reliance on microtransactions to speed up progression and a potential for repetitive gameplay that may not appeal to all players.

8. What other games have been developed by the same developer:
Zynga, the developer behind FarmVille 2, has an extensive portfolio of popular games including CityVille, CastleVille, Zynga Poker, Mafia Wars, and Words With Friends. They are known for their expertise in creating engaging social games that connect players around the globe.