A game genre is a type or category of game. As with movies, there are many game genres, and they are often hard to classify. Some games may fit in more than one genre. Here's a list of the most popular genres.
Action An action game has moving objects and focuses on your timing, reflexes, hand-eye coordination, and quick thinking to achieve a good score. Most games have some action in them but aren't necessarily considered "action games." Space Invaders and Half-Life are good examples of action games.
Adventure Often confused with RPGs, adventure games let you control a character in an environment while the story is discovered. Unlike what happens in an RPG, your actions do not affect your character's overall abilities. Examples of adventure games range from Super Mario Brothers to the games in the King's Quest series.
Casino One of the most popular genres to play on the Internet is casino (that is, gambling) games, such as poker and roulette.
Educational In an educational game, the goal is to educate the player. This game can also be a part of another genre; for instance, you can have an educational puzzle game.
First-person shooter This style of game lets you see a world through the character's eyes as you run around and try to shoot anything that moves. Typically the action in these games takes precedence over the story.
Puzzle A puzzle game, also called a logic game, challenges your mind more than your reflexes. Many puzzle games are timed or limit the amount of time in which you can make a move. Games like Tetris and Sobokan are good examples of puzzle games. Puzzle games also include some classics like chess and checkers.
Sports A sports game is an action game with rules that mimic those of a specific sport. For instance, NHL 2002, by Electronic Arts, is an ice hockey sports game.
Role-playing game (RPG) An RPG is a game in which you, the game player, control a character in its environment. In this environment you encounter other beings and interact with them. Depending on your actions and choices, the character's attributes (such as fighting ability, magical powers, and agility) change, and so may the story. Baldur's Gate is an RPG.
Strategy This type of game focuses on your resourcefulness and deal-making ability as you try to build and/or run something. In some games, your goal is to successfully build and run a city; in others, what you have to build or run can be anything from an army to a roller coaster.