1. Introduction of the game:
Clash Royale is a real-time strategy game that combines elements from collectible card games, tower defense games, and multiplayer online battle arenas. Developed by Supercell, this game manages to deliver quick and engaging matches that require strategic thinking and tactical execution. Players collect and upgrade cards featuring Clash of Clans troops, spells, and defenses, as well as the Royales like Princes, Knights, and Baby Dragons. The objective is to defeat opponents in battle by destroying their towers, with the ultimate goal of achieving the highest possible ranks.

2. All characters and levels of the game:
Clash Royale features a diverse range of characters, known as cards, which include troops, spells, and buildings. Characters like the Archer Queen, Bandit, and Electro Wizard, alongside numerous spells and defenses, offer a wide array of tactical combinations and deck strategies. The levels of the game pertain to the player's experience level, card levels, and the arenas they progress through – each offering unique backdrops and increased challenges as players climb the ranks from Goblin Stadium to the Legendary Arena.

3. What attracts users most to the game:
Players are attracted to Clash Royale for its competitive gameplay, quick-paced matches, and the depth of strategy required to outmaneuver opponents. The allure of collecting and upgrading a wide variety of cards, building personalized decks suited to one's playstyle, and climbing the global leaderboards provide an addictive and dynamic gaming experience.

4. Why it is popular:
Clash Royale has garnered popularity due to its accessibility, allowing players to engage in bite-sized battles that are perfect for on-the-go gaming. The game's free-to-play model, combined with the fairness of its in-game economy, allows players to enjoy the game without mandatory purchases. Regular updates, challenges, and in-game events have kept the game fresh and maintained a loyal player base.

5. The most difficult part of the game:
One of the most challenging aspects of Clash Royale is mastering the intricacies of deck building and real-time strategy against a diverse range of opponents. As players progress to higher arenas and reach the endgame, they face highly skilled players, necessitating a deep understanding of card interactions, timing, and positioning.

6. Strengths and weaknesses of the game:
Strengths of Clash Royale include its compelling gameplay, strategic depth, and strong replay value. The game's ability to balance simplicity with complexity allows it to cater to both casual and hardcore gamers. Weaknesses might include the grind required to upgrade cards without spending money, which can be time-consuming, and the occasional frustration players may feel when facing over-leveled opponents.

7. What other games have been developed by the same developer:
Supercell, the developer behind Clash Royale, is known for several other successful mobile games, including Clash of Clans, Hay Day, Boom Beach, and Brawl Stars. These games all share Supercell's signature charm, addictive gameplay, and a strong emphasis on social interaction and competition.