I'm new to the Witcher series but I've been reading a lot about this game, so far this is what I've come up.

About the game

• The devs are Polish and most of them grew up playing the Gothic series. Both series are a story-driven single-player cRPG with TPP camera and a predefined character - so you can equip/skill up your character, but cannot change their name or face. A key element of Gothic was an open world with no scaling - the strength of your character defined which areas you could go to and which were certain death (in the beginning, pretty much everywhere). Witcher 1 and 2 are open within a certain location (usually one set of locations per chapter). Witcher 3 is going to be fully open.

• Other games from the past with similar controls would be The Elder Scrolls (Morrowind, Oblivion, Skyrim) and Fable series, but they are very much different in many aspects. TES is a sandbox with scaling enemy level (there is no difference in order of doing A and B, the first one will be always "easier") and plethora of side quests that outshine the main quest (and have no correlation with each other, so you can join the Thieves Guild as Archmage and nobody wil notice). Gothic and Witcher are series oriented around the main character (unlike in the other two series, the main character speaks) and main quest.

• A parallel, similar series would be Dragon Age, which is somewhere between The Elder Scrolls and The Witcher, but a bit different (emphasis on companions compared to these two).

• Combat system in the second game (but not the first) bears resemblance to Dark Souls, but it's not as mechanically challenging. Instead, it puts emphasis on the RPG elements and adjusting methods to the enemy you are going to fight.

Setting

• "The Witcher" series is based on books by a Polish author Andrzej Sapkowski. Not all of the books are translated to English yet, but there are OK-ish fan translations of the remaining ones.
• The world is a fantasy setting, somewhere betwen typical high fantasy and dark fantasy. There are Nordic, Celtic (Arthurian legend) and above all, Slavic elements in it.
• The story occurs mostly in Northern Kingdoms, which are threatened by the southern Nilfgaardian Empire (where some of the action in the books takes place). Games are set in the Northern Kingdoms.
• Action of games takes place after the books, and the first two games portray the world and numerous previously known characters, but don't expand on the main story from the books (the typical amnesia cliche, but it makes sense here).
• The third game brings back characters from the book saga - Geralt's on-and-off lover sorceress Yennefer and their more or less adoptive daughter, Ciri. So it's okay to jump in and start from TW3, but any prior contact with the story greatly enhances your experience.

Main character

• Geralt is a witcher, a breed of mutated humans made to fight monsters and undo curses.
• Witchers are mercenaries, looked down upon by the society as abnormal, immoral and overall disgusting.
• Witchers are becoming obsolete. They've served their purpose and even though there are still some monsters, the knights and soldiers are learning how to fight them - and with development of magic, curses are being dealt with as well.
• Witchers have their strength, agility and senses enhanced magically and chemically, followed with years of rigorous training.
• They fight with swords, drink potions, set up traps and use few basic psychokinetic magic tricks (Signs).
• No new witchers have been made in decades. The current ones are older than they look and no witcher has ever died of "natural causes" as they're immune to diseases. The oldest one, Vesemir, is over 300 years old.
• Geralt is overall a cynical and scrupulous man and saving the world is the least of his worries, unless it's paid well. All events he's involved in are either paid jobs or personal matters, no charity for the glory of it.
• Grey morality - there are no "good" and "bad" options, all are shitty, you just have to choose which one is less harmful to you and the people you like.
• Choices you made in the past chapters come back to haunt you later on, as you learn the consequences of your actions, often unforseen.

Thanks for this giveaway, I'm really excited for this game and it's one of my most anticipated game of 2015.