A solid game with a great story, but held back by coherency problems and a lack of character development options.
The game starts off with an attack on the witcher fortress of Kaer Morhen. After a rather unsuccessful effort to defend the fortress and its secrets, you set out to find your assailants and recover what they have stolen. A simple premise, but it's very effective at setting up the first chapter of the game. Obviously, you play the aforementioned Geralt of Rivia, who, sadly, suffers from amnesia. It's a cheap trick to pull but it works to the game's advantage in many ways. You're basically given a blank slate which you can mold to your liking... morally at least, the stat aspect is rather limited (more on that later).
The story, for sure, is the game's most interesting element. It successfully interweaves political, racial, religious and mythological themes into one layered whole. And while it doesn't give you much breathing room, there are interesting choice & consequence moments which define and individualize your playthrough. The main characteristic of these moments is that consequences aren't obvious right away. In fact, most consequences show up at a later date in the game, and until that point the choice you made might seem irrelevant. It's an interesting feature that adds a lot to an otherwise linear main story.
Where the game does give you some breathing room is side questing. You're free to explore the areas available to you (each chapter unlocks new areas while sometimes locking you out of older ones) and you'll find plenty of witcher's work to keep you occupied, as well as unique loot to discover in some dark crypt or dungeon.
Now for the bad news. In my view, the biggest weakness of The Witcher is its rather incoherent story presentation, which is most obvious during dialogue sequences. Sometimes, one character will say something and the other character will follow up with something that seems completely unrelated. You'll literally need a few moments to figure out what was said and how it fits into context. It's obvious (sometimes painfully so) that the English translation isn't what it should have been, and neither is the voice acting for that matter. It's a shame, because the writing is quite good, and, as mentioned earlier, so is the story, when you get passed these issues. Lastly, important story moments usually feature cutscenes, dialogue, and action sequences, and the way they succeed each other feels clunky at times. It's obvious that the engine used by the CD Projekt team (a heavily modified version of Bioware's Aurora engine) was not made for the cinematic experience that the devs tried to achieve.
Underneath the great story and the presentation issues lies a solid RPG. When talking about the core game mechanics, the alchemy system (mix ingredients to get various potions, oils, bombs) and the interface are to be commended, while the character system... well, it ain't too hot. You basically get to invest talent points into various areas (like basic attributes - strength or dexterity for example - or spells, or sword styles) and gradually improve your character. There's not much in terms of personalization options here, most talents consist of adding 10% more damage to one of your sword styles, or 20% resistance to pain and bleeding effects. That sort of stuff. As for combat? It's basically you clicking an enemy till it dies. The most important decisions you need to make in this regard is what weapon and combat style you'll use, while also adding potions, bombs or blade coatings to the mix if need be. There's a list of spells as well, though it's limited (you have your basic fireball, a push spell, charm person and so on); The Witcher is a rather low-magic setting. So yeah, combat is by no means impressive or exciting, the best thing I could say about it is that at least it's not frustrating or annoying.
An aspect that I absolutely loved about this game is the fact that it makes information feel important. From basic stuff like knowing the many different types of plants useful in alchemy, to more vital stuff like knowing the weaknesses and strengths of a monster, information actually matters. Getting your hands on books and alchemical formulae is something you'll want and need to do. Also, besides this knowledge that's vital for survival and moving the story forward, there are books that are lore related only, and serve only the purpose of giving more contour to the game world. A noble purpose if you ask me, a setting can never be fleshed out enough.
One complaint I really feel the need to make is the lack of a fast-travel system. Areas are pretty big in general, so there's too much walking around and too many loading screens; all this artificially lengthens the game by quite a bit. It would have been great if the devs gave you the option of traveling to some of the more important locations directly every time you reach an area exit. For example, I'm in the Temple Quarter and I want to reach the Narakort Inn in the Trade Quarter. Why not let me choose from a map of the city to go directly to the inn when I reach the Temple Quarter exit? This way I don't have to go through multiple loading screens and walk around large portions of both quarters.
On the tech side, The Witcher impresses with its good looks and impressive sound. It's amazing what CD Projekt did with the Aurora engine, specially in comparison to what other devs managed (or rather didn't manage) to with it. Bioware and Obsidian could both learn something from these ambitious Poles. The smooth day/night transition and the weather effects, coupled with great sound effects, an excellent soundtrack, and NPCs that actually go about their business instead of just standing around, really make this one atmospheric gaming experiences.
I'd also like to mention that the Enhanced Edition ships with two short complementary adventures, which are nice I might add. Both are about an hour in length and have interesting enough stories. Obviously, you're not going to save the world in either of these, they're more on the lighthearted side. It's a nice gesture on the part of the devs.
To conclude, The Witcher is a very enjoyable game, but coherency problems and lack of character development hold it back from being a true classic. But, is it worth trying out? I'd answer yes, definitely!