JRPG - Short for "Japanese RPG". A broad term, but in modern vernacular it's generally used to refer to a Japanese-developed RPG that puts less emphasis on raw statistics and dice rolls and aims to be a more character and story-driven experience.
Western JRPG - A game that, while created by western developers, plays much like a Japanese RPG.
CRPG - Short for "Computer RPG". Another broad term, but in modern speak it generally refers to a game built to resemble a Dungeons and Dragons styled experience, placing heavy emphasis on character stats and dice rolls to determine success for almost every action taken.
Roguelike - Related to CRPGs, but generally designed to be a shorter, "one-off" experience. Usually marked by heavily randomized content, a high difficulty level and complex, esoteric mechanics.
Strategy RPG - A game where the battlefield itself is as much a part of fights as the characters in it. Utilizing cover, overcoming obstacles and using terrain to your advantage are key parts of battle. Almost always turn-based.
Action RPG - Any action-oriented game with RPG elements worked in, usually in the form of stats, skill trees and experience levels.
Monster Breeder - Much of the game's emphasis is placed on capturing, raising and training monsters to serve as your primary fighting force in battles.
MMORPG - Short for "Massive Multiplayer Online RPG"; essentially, a game with online servers where most of the characters in the game world are actual players, all playing within a single continuous virtual "world" on the server. Typically these are more action-oriented games with an emphasis on complex mechanics, large amounts of content and player interaction, whether cooperative or competitive.
Fantasy - Heavily influenced by mythology and folklore and generally set within a lower-technology world, with a few exceptions (airships and steampunk cities, for example).
Science Fiction - A more futuristic setting, prominently featuring advanced technology and only a few (or no) fantastic elements.
Science Fantasy - A game world in which science fiction and magical/mythological elements coexist and play roughly equal part in the setting.
Historical - A setting that is based on events from Earth's past, though obviously fictionalized.
Urban Fantasy - A relatively modern setting with some fantastic elements.
Freeform Characters - The player is not constrained by predetermined classes or archetypes - they can pick any skills, equipment or abilities they like and use them freely.
Customizable Characters - While the player is restrained to prefabricated classes, they are afforded the opportunity to customize their character(s) equipment sets or skill loadouts, adding some variety.
Prefab Characters - Characters in the game have their abilities and equipment types set in stone, with little to no opportunity to customize them.
Brutal Violence - The game contains significant amounts of blood, gore and carnage. Not for the squeamish.
Disturbing Themes - Dark elements other than violence - bizarre/upsetting imagery, psychological torment and general cruelty.
Sexual Content - Strong, pervading themes on the subject or outright depicting the act.
Strong Language - Lots of four-letter words.
Turn-Based - Combat in the game, or the game as a whole, operate on a turn-based system, with the player and enemies taking actions in equal measure.
ATB-Like - Named after the Active Time Battle system made famous by the Final Fantasy franchise. While combat is still broken into distinct "Turns", they also operate on something of a time scale; actions require different lengths of time to actually take place, allowing other characters to delay their opponents' turns or even cancel them entirely. One particularly famous example is Grandia, where a significant part of the game's strategy is suppressing opponent's more powerful attacks by cancelling their turns.
Real-Time Combat - While battles in the game are still set in a distinct "combat mode", they operate in real-time. The player may still have the ability to pause the action to change equipment or use items.
Random Encounters - Basically, you don't see fights with standard enemies coming until you're already fighting them, and their appearance is determined by a mathematical algorithm. Generally a hallmark of older RPGs, where it was born of a technical limitation that allowed only a set number of sprites to be drawn on screen at a time, though it appears in some modern games as well.
Visible/Scripted Encounters - The majority of enemies in the game are visible on the map or battles are triggered in fixed locations, which allows the player a chance to avoid them if they don't wish to fight (most of the time, at least).
Combat Minigames - "Minigame" is a general term referring to a smaller game within a larger one, usually granting some kind of reward in the main game (or being just for fun). In this case, minigames are integrated into the game's combat, with things like timing-based tests or slot machine reels governing the effectiveness of attacks.
Mechanical Minigames - Minigames that aren't integrated into combat, but still play a significant role in the overall gameplay. One famous example is the lock-picking minigame in the modern Elder Scrolls and Fallout games.
Optional Minigames - Minigames that, while they may occasionally be required to progress through the story, are mostly optional diversions with no direct bearing on the storyline.
Dungeon Crawler - The game as a whole is focused around making one's way through a large dungeon (or several large dungeons) and overcoming the many puzzles, traps and dangers within. Roguelikes tend to fall under this category by default.
Randomized Content - Large portions of the game are randomized each time one begins a new game or revisits a particular area, ensuring the experience will never be quite the same twice.
Collection-Fest - A substantial portion of the game is spent collecting large amounts of items, whether "loot" (various randomized equipment) or just mundane things that can be used in pursuit of a higher goal (such as rebuilding a town). Usually goes hand-in-hand with a Crafting system, though not always.
Crafting System - Collecting items and refining them into other items is a significant part of the game - usually things like potions, weapons and structures for a town-building element. The Elder Scrolls franchise famously takes this even further, allowing the player to build their own equipment enchantments, potions and even custom-made spells.
Multiple Story Paths - The player is given the option to take the story in a much different direction at key points, resulting in a divergent narrative and possibly alternate endings.
Voluminous Side Content - Content not related to the main story is abundant, equalling the main narrative in depth and time investment or even surpassing it. Elder Scrolls is a famous example of this, having hundreds of optional areas and quests that have no direct relevance to the main storyline.
Grindfest - The game requires a significant amount of time spent doing mundane stat/item/level farming in order to succeed. Generally a mark of older RPGs, where it was used as a somewhat inelegant way to lengthen the experience, though it does appear in some newer games as well.
Long Animations - Spell and attack animations are overly long, which can slow the game down over long periods and add much running time to the game.
Long Load Times - The game takes a significant amount of time to load cutscenes, battle scenes, and so forth, which can slow down the game a lot in the long run.
Unskippable Cutscenes - Dialog and cutscenes cannot be skipped, which can lead to frustration when particularly difficult boss fights occur after long sequences of them.
Adjustable Difficulty - The game has multiple difficulty settings, allowing it to be accessible for less experienced gamers but challenging for more seasoned ones.
Extreme Difficulty - Simply put, the game is extremely difficult and will require a lot of skill, mastery of mechanics and patience to complete.
Fake Difficulty - A game which is difficult, but for inauspicious reasons. Lousy stage design, poor documentation of features, an unintuitive interface, badly implemented mechanics, et cetera.
Save Anywhere - Simply put, the player can save their progress when and wherever they choose. Often, the player is not allowed to save in combat in order to reduce the risk of making their game unwinnable.
No Saving in Dungeons - The player can save progress anywhere on the world map, or in set locations within indoor areas, but not at any point of their choosing.
Save Only at Checkpoints - The player is only allowed to save at predetermined points - usually inns or conspicuous "save icons" scattered through the world.
Automatic Saves - The game is automatically saved at certain points. The player may not have the ability to save their game manually.
In general terms, how long it takes to make one's way through the main storyline of the game.
Very Short Campaign - 10 hours or less.
Short Campaign - 10-20 hours
Mid Length Campaign - 20-35 hours
Long Campaign - 35-55 hours
Very Long Campaign - 55 hours or more.
Downloadable Content (Great) - Has downloadable content that adds much to the overall game experience and is well worth the asking price.
Downloadable Content (Meh) - Has downloadable content that is dubious in value. You probably won't regret buying it, but it doesn't add much to the experience overall.
Downloadable Content (Ripoff) - Downloadable content that ends up being a waste of money - it either subtracts from the game or adds too little to it be worth the asking price.
Cinematic Experience - The game goes for a movie-like feel with grandiose set pieces, tense action segments and a relatively fast pace. Basically, a summer blockbuster in RPG form.
Great Music - The game features a fantastic soundtrack that perfectly compliments the mood the game is going for, and is still a great listen even outside the context of the narrative.
Humorous - The game has a strong sense of humor, whether self-aware or just containing funny jokes.
Cringe-Worthy - A game that makes me cringe - bad writing, poorly-implemented design elements, terrible voiceover, or jokes that fall flat at every turn.
Japan Exclusive - A game that was only released in Japan and is not available elsewhere in any official capacity. Fan translations may exist, however.
Bugs and Glitches - The game has programming errors that hamper the gameplay experience at times or can potentially make a game unwinnable. If these are fixed in official patches, this tag may be excluded.
Missables - Particular items or events can be easily missed, which may rob the player of 100% completion or otherwise very useful advantages. You may want to have a guide handy for this one.
New Game Plus - The game features a way to start the game over while retaining some (or all) of a character's experience, items and/or money, making the next playthrough quicker and easier. Some games also take advantage of this by providing multiple endings or new story paths that can only be accessed on a second playthrough or later.
Direct Sequel - The game is a direct sequel to another game and playing that one first is recommended, lest you miss out on large portions of the running storyline.