1. Introduction of the game:
Welcome to the world of Angry Birds, a wildly addictive mobile game that has captured the hearts and screens of millions around the globe. In this physics-based puzzle game, players are tasked with slingshotting a variety of angry birds into structures occupied by evil green pigs. With their unique abilities, the birds aim to retrieve stolen eggs and seek revenge on their nefarious adversaries.

2. All characters and levels of the game:
Angry Birds features a colorful cast of characters, each with their own special abilities. The original lineup includes Red, the strong and versatile leader; Chuck, the high-speed yellow bird; Bomb, the explosive black bird; Matilda, the egg-laying white bird; and the versatile blues, Jim, Jake, and Jay. As players progress through the game, they unlock additional characters, such as Hal, the boomerang bird, and Terence, the massive, destructive bird.

The game boasts a wide variety of levels, each presenting unique challenges and puzzles to solve. From simple wooden structures to elaborate stone fortresses and icy landscapes, players must strategically aim their birds to efficiently topple the pigs' defenses and rescue the stolen eggs.

3. What attracts users most to the game:
One of the main attractions of Angry Birds is its simple yet highly addictive gameplay. The intuitive controls and straightforward objective make it easy for new players to pick up and enjoy. Additionally, the humorous and vibrant character designs, combined with the satisfaction of successfully completing each level, keep users engaged and coming back for more.

4. Why it is popular:
Angry Birds has garnered immense popularity due to its widespread accessibility and universal appeal. Its charming visuals, challenging puzzles, and addictive mechanics have captivated players of all ages and backgrounds. The game's ability to strike a balance between casual entertainment and strategic thinking has undoubtedly contributed to its widespread success.

5. When the game was released and how many versions are currently available:
Angry Birds was first released by Rovio Entertainment for iOS devices in December 2009. Since then, it has expanded to various platforms, including Android, Windows, and gaming consoles. Currently, there are multiple versions available, including Angry Birds Classic, Angry Birds Space, Angry Birds Rio, Angry Birds Star Wars, and many more spin-offs and sequels.

6. The most difficult part of the game:
The most difficult part of Angry Birds lies in mastering the trajectory and timing of each bird's launch. As players progress through the game, levels become increasingly challenging, requiring precise aim and strategizing. Additionally, some levels feature complex structures and ingenious pig placements, testing the player's problem-solving skills and patience.

7. Strengths and weaknesses of the game:
One of the key strengths of Angry Birds lies in its addictive gameplay, characterized by its simple mechanics and progressively challenging levels. The game's humorous and visually appealing design adds to its appeal. However, some players may find the repetitive nature of aiming and launching birds to be a potential weakness. Furthermore, in-app purchases and ads can sometimes interrupt the flow of gameplay.

8. What other games have been developed by the same developer:
Rovio Entertainment, the developer behind Angry Birds, has expanded its portfolio with several other successful games. Some notable titles include Bad Piggies, a spin-off in which players control the pigs; Angry Birds Epic, a role-playing game set in the Angry Birds universe; and Angry Birds Transformers, a hybrid of shooter and racing genres. The developer has also ventured into non-Angry Birds franchises, offering games like Battle Bay and Love Rocks starring Shakira.