Dull gameplay is overshadowed by a believable, dark atmosphere and story, and untraditional, game-changing choices.
I'll start with the downfalls of the Witcher. The combat is interesting and fun - at least, for the first thirty minutes or so. But eventually, it becomes more of a chore when it should be the exciting centerpiece of the game. This is probably because the combat itself is very, very, basic - quite simply, you click to attack, and click again to attack again once your attack animation is finished. There's a few more elements - for example, a few magical signs do spice up the action a bit, and you have to ability to do a quick dodge to get out of harm's way - but in the end, there's not much to it. Of course, the combat wouldn't be nearly as bad if it wasn't so overly frequent. There are multiple areas in the game where you can't walk ten feet without attracting hostile attention. Later on in the game, this attention often comes from enemies that are so weak that they offer no substantial reward for slaying. Thus, combat eventually became a chore. And when it wasn't tiresome, it was just too difficult - I can recall numerous times where I kept getting knocked down, stunned, immobilized by pain, and the such without being given the chance to get a few good attacks out.
From a visual standpoint, the game was average. The actual graphics - the texture detail and effects - fit well into the atmosphere of the game and weren't an eyesore. But, many of the animations were flawed (how am I killing this monster if my blade is stabbing the air above its head?) and repetitive (generally, you won't see more than 6 or so animations per battle. Compare this to the almost endless amount in Arkham Asylum, which is only a couple years newer).
Aside from the combat, the rest of my disappointment in the Witcher rested in minor nuisances and flaws. For example, it crashed every so often (at least for me, may not be a problem with the game). The entire game seemed to consist of about ten different character models. There was no way to pass time without finding a fire, lighting it (which requires an item without a certain spell), and meditating - which is unfortunate, since many quests require you do something at a certain time. Things like this are the difference between a great game and a good one.
But then, the Witcher was still worth a play. The game is different from other RPGs, and you will notice this a lot. Rather than other RPGs - say, the Dragon Age series - which boast vibrant, colorful worlds with unique races, the Witcher presents a dark world - true to the Medieval era that many RPGs claim to represent - in which corruption reigns free. "Real" issues, such as racism (against non-humans, in this case), drug addiction, and bribery play huge roles in the story.
The element of choice, however, is by far the most noticeable feature of the Witcher. The choices you make in the game aren't bound by a strict law of good and evil. Rather than other RPGs, where a typical choice can range from helping a mugging victim or killing his attackers and taking his money yourself, to saving the world or dominating it, a choice in the Witcher may be as complex as choosing whether to help a borderline terrorist group who is fighting for equal rights and an end to violent discrimination, or helping their enemies - who are discriminatory, religiously overzealous knights. In the end, it isn't good or bad, but the lesser of two evils. Plus, your choices have enormous impacts on the gameplay - with a nifty flashback to remind you how your decision earlier in the game affected a current event - giving the game some replay value.
The story is involving, though not as good as some I've seen. It doesn't take too many twists and turns - your enemy at the beginning remains static throughout the majority of the game. That being said, it's filled with realistic themes of corruption, betrayal, deception, and lies that you could expect from a "dark ages-like" era.
The bottom line? It's a fun game, but not much more. I personally only played it because I bought the second one and wanted to get the story of the first one. And had that not been driving me, I'm not sure I would have finished the game. It isn't anything spectacular, but people who like games that shatter the widely accepted norms for a genre will enjoy the Witcher's dark atmosphere and story, and especially its unique system of choices and consequences.