1. Introduction of the game:
Gems of War is a captivating puzzle RPG game that blends classic match-3 mechanics with deep strategy elements and character collection. Developed by Infinity Plus 2, this innovative title combines the thrill of gem matching with a high-fantasy narrative, allowing players to engage in battles, complete quests, and conquer kingdoms. By matching colored gems and skulls, players power up spells and abilities to outwit their opponents across a richly-detailed world.

2. All characters and levels of the game:
Gems of War boasts an extensive range of characters, each belonging to various classes and races. There are over 700 unique troops that players can collect, level up, and evolve, hailing from more than 30 kingdoms. Players can assemble teams that best suit their strategic preferences, using character abilities to gain an advantage during play. The game is structured into various levels and kingdoms, each presenting unique challenges and stories. As they progress, players unlock new areas and delve into the lore behind each faction and hero.

3. What attracts users most to the game:
The combination of match-3 gameplay with RPG elements, such as team building and character progression, offers a layered gaming experience that keeps players engaged. The constant introduction of new events, troops, and features provides fresh challenges and strategies. Additionally, the game’s social aspects, including guilds and PvP, attract users who enjoy both cooperative and competitive play.

4. Why it is popular:
Gems of War has gained popularity due to its unique gameplay fusion, free-to-play model, and its ability to provide a sense of continuous achievement. The regular updates, combined with the depth of collectible characters and the strategic complexity of team-building, ensure that both casual players and hardcore gamers have something to enjoy.

5. The most difficult part of the game:
For many players, the most challenging aspect of Gems of War is tackling the endgame content, where strategic team composition and understanding intricate synergies between troop abilities are pivotal. Certain high-level PvP matches and guild events can also present significant challenges, demanding a deep knowledge of game mechanics and meta-game trends.

6. Strengths and weaknesses of the game:
Strengths of Gems of War include its addictive gameplay blending, the extensive range of characters, and the strategic depth provided by both team-building and in-match decision-making. Weaknesses might include a steep learning curve for newcomers, occasional balance issues with certain troops or classes, and the reliance on grinding or in-app purchases to progress at the fastest rate.

7. What other games have been developed by the same developer:
Infinity Plus 2 is also known for developing the similarly styled and highly successful game Puzzle Quest, an earlier title that also blended match-3 elements with RPG gameplay. Puzzle Quest's success paved the way for its sequels and spin-offs, as well as games like Gems of War that build upon the same successful formula.