1. Introduction of the Game:
PJ Masks: Racing Heroes is an exhilarating mobile game that thrusts players into the adventurous world of the beloved children's TV series, "PJ Masks." Designed with vibrant graphics and exciting gameplay, this racing game challenges players to buckle up and race the PJ Masks to the moon! As players embark on this epic journey, they will navigate their way through a series of lunar landscapes in a quest to defeat the mischievous night-time villains and reach the moon.

2. All Characters and Levels of the Game:
The game features the iconic trio from the PJ Masks series: Catboy, Owlette, and Gekko, each with their unique vehicles - the Cat-Car, Owl Glider, and Gekko-Mobile. As players progress, they traverse multiple levels with increasing difficulty, including cityscapes at dusk, rooftops under the cloak of night, and finally, the enigmatic lunar plains. Each level offers unique challenges and obstacles to test players' racing skills.

3. What Attracts Users Most to the Game:
Users are most attracted to PJ Masks: Racing Heroes for its engaging gameplay and the chance to step into the shoes of their favorite nighttime superheroes. The game's ability to blend simple controls with challenging obstacles creates an addictive experience for fans of all ages. Coupled with the thematic ties to the PJ Masks universe and the chance to upgrade vehicles and power-ups, it provides an exciting draw for the show’s young fan base.

4. Why It Is Popular:
PJ Masks: Racing Heroes has gained popularity due to its association with the popular children's series and its appeal to young fans who dream of joining their hero’s exciting adventures. Moreover, the game provides a child-friendly interface, thorough entertainment, and a sense of accomplishment as players beat levels and reach new heights.

5. When the Game Was Released and How Many Versions Are Currently Available:
PJ Masks: Racing Heroes was released in December 2018. Since then, the game has been updated with new features and bug fixes to enhance the user experience. there may be several versions of the game available, with the latest updates following its initial release. For the most current information, users should refer to the app store listings.

6. The Most Difficult Part of the Game:
The most difficult part of PJ Masks: Racing Heroes is likely the progressive increase in difficulty with each level, introducing more challenging villains and obstacles that require skillful maneuvers and quick reactions to overcome, especially for the game's younger audience.

7. Strengths and Weaknesses of the Game:
Strengths of the game include its engaging graphics, true-to-show character representation, and intuitive gameplay mechanics that are well-suited for its target audience. Conversely, the game's weaknesses may lie in a possible lack of depth and variety for more experienced gamers, as well as limited content that might not offer much replay value beyond the initial playthrough.

8. What Other Games Have Been Developed by the Same Developer:
PJ Masks: Racing Heroes was developed by Entertainment One, which has also produced other games based on its popular franchises, including several other PJ Masks titles such as 'PJ Masks: Moonlight Heroes', 'PJ Masks: Super City Run', and 'PJ Masks: Time to Be a Hero'. They have also expanded their portfolio to include games from different licenses, providing an array of options for fans of their various series.