The Witcher has three possible endings that depend entirely on the actions you take in the game. On top of the multiple endings each of the actions that lead to them have different in-game consequences. Supporting one group of people over another, or taking a neutral stance, will affect the game multiple chapters down the road. For example, you are tasked by a merchant to kill some monsters that have been interfering with his business. After you are finished with them you notice a group of people are starting to run off with the merchant's stuff. How you respond to this situation will make the next chapter more or less difficult but I won't say how. The Witcher is full of little choices and paths like this. There are a number of sidequests that are not necessary to the main plot but help to flesh out the world and, of course improve your character through money, equipment and experience. There are also two minigames that can be found throughout the course of the game, fistfighting, essentially drunken brawling, and dice poker. Both are the subject of own, entirely optional quests. Dice poker is played by rolling a set of five dice, looking for doubles, triples, straights and the like while fistfighting and drinking games are accomplished as you would think - hitting things and drinking things.
