Character traits.
The main character(s) and other characters and enemies (more often to a lesser extent) have a number of parameters (abilities, characteristics, skills) that determine their strengths and abilities. Usually, the main characteristic of characters and enemies is the level, which determines the overall strength of the character and determines the available skills and equipment items. All of these parameters must be improved by killing other characters and enemies, completing tasks and using these very skills.
There is a detailed and extensive world, a strong storyline, ramified dialogues with different answers, a lot of different characters with their own goals and characters.
A large number of different items: equipment, potions, artifacts, etc.

Subgenres
Action RPG – shooter or beat ’em all with a fully developed RPG elements, including complex quests and advanced leveling system. At the same time the game is a full-fledged shooter or beat ’em all.

Examples: Deus Ex, Hexen 2.
Hack’n’Slash RPG – RPG with an emphasis on slaying enemies, collecting the most powerful things, pumping characteristics. Usually have a simplified world and the plot, a small number of dialogues and options for solving quests and other problems. Examples: Diablo, Dungeon Siege.
true RPG (also simply RPG or CRPG) – role-playing game with a large number of dialogues, freedom in choosing how to solve various problems, developed the world and the plot. Examples: Fallout, Planescape: Torment, Baldur’s Gate.
JRPG – (Japan RPG) role-playing game with an elaborated world and dialogues, but with less freedom of choice, often has a very exciting, but linear story, the lack of choice in boosting character stats, as well as a very well developed and beautiful characters. The game is somewhat like an interactive book. It is often created by Japanese developers, and there are very few games of this kind, created outside of Japan. Examples: Final Fantasy, Skies of Arcadia.

Tactical RPG
Main article: Tactical RPG
A genre of role-playing games that is a mix with turn-based strategy. The player controls a small group of warriors, although in some tactical RPGs their number can be up to several dozen. The first tactical RPGs appeared on consoles in Japan. Today, however, there are many Western and computer-based tactical RPGs.

Examples:

  • Fallout Tactics series game.
  • Jagged Alliance series
  • Silent Storm series
  • X-COM (UFO) series
  • Bitter 17 and Bitter 18 series

Examples of console tactical RPGs:

  • Fire Emblem series
  • Langrisser series
  • Shining Force series