1. Introduction of the game:
Crossy Road is an engaging and whimsical arcade game developed by Hipster Whale that challenges players to navigate their character across a series of endless, hazardous roads, rivers, train tracks, and other obstacles. With simple tap and swipe controls, the objective is to get as far as possible without being crushed, drowned, or meeting other untimely ends, while collecting coins and unlocking new characters along the way.

2. All characters and levels of the game:
The game boasts an extensive collection of characters, each with its unique design and sometimes with their own special sound effects and environments. These characters range from the classic Chicken to a variety of animals, pop culture figures, and even mythical creatures. There are no traditional levels in Crossy Road, as the game features an endlessly generating sequence of obstacles that progressively get more challenging as you move forward.

3. What attracts users most to the game:
Users are most attracted to Crossy Road's simple yet addictive gameplay, diverse character roster, and charming pixel art graphics. The game's ease of picking up for a quick play session coupled with the difficulty of mastering it keeps players coming back. Additionally, the frequent updates and addition of new characters keep the experience fresh and engaging.

4. Why it is popular:
Crossy Road's popularity can be attributed to its accessible gameplay that caters to all age groups, its endearing retro-inspired graphics, and social sharing features that promote competition among friends. Moreover, its free-to-play model with non-intrusive optional in-app purchases ensures that the game is available to a wide audience.

5. The most difficult part of the game:
The increasing pace and complexity of obstacles are the most difficult parts of the game. As players progress, they must contend with faster-moving vehicles, wider rivers, and more frequent trains, all of which require quick reflexes and precise timing to overcome.

6. Strengths and weaknesses of the game:
Strengths of Crossy Road include its addictively simple gameplay, a vast array of characters, family-friendly content, and the fact that it can be played without an internet connection. However, its weaknesses might include a repetition that can eventually lead to gameplay feeling monotonous for some, and a reliance on chance in unlocking certain characters, which can be frustrating for players looking to collect them all quickly.

7. What other games have been developed by the same developer:
Hipster Whale, the developer of Crossy Road, has also released several other games including "PAC-MAN 256," which combines the classic Pac-Man experience with an endless runner style, and "Piffle," a cute arcade puzzle game. Hipster Whale has also collaborated on the development of the multiplayer version titled "Crossy Road Castle" and the Apple Arcade exclusive "Crossy Road+" delivering different twists on their original hit.