The Witcher is, as the title suggest, a "solid, unique single-player CRPG". Using Bioware's Aurora engine to bring the world to life, The Witcher offers a highly unique dark-fantasy vision (based on the best-selling Polish novels). Yes there are dwarves and elves and magic, but don't mistake this for a pure Lord of the Rings ripoff. There's a heavy dose of racism, rape, prostitution, murder and betrayal involved in the engaging and quite adult (in theme) storyline.
The gameplay is a nice change of pace, with a focus purely on swordplay and limited "magic". Rather than just a Diablo-like clickfest, The Wticher adds a small amount of timing-based combo to the mix and three different attack styles (strong, fast, and group), which keeps the pace moving well.
For those who expect a lot of stat-management, you'll be disappointed, as The Witcher features minimal to no customization opportunities, save for upgrading attack styles and four basic stats. Hats off to the dev team for the beautiful (if slightly confusing) GUI for inventory and ability management.
On a final note, the Witcher offers three camera modes that drastically change the underlying feel of the game. There's a low and high isometric view that duplicates what is seen in Diablo or Dungeon Siege, giving the game a tactical and detached feel to it, or you can choose an over-the-shoulder viewpoint that greatly increases engagement in exchange for the tactical overview. I preferred playing OTS since it helped sell the beautiful and engaging setting.
It runs half-way decent on a solid PC, but the Aurora engine is not known for its efficient use of computer resources. Expect some chugging if you crank it up to max, even if you can handle some better looking games with ease.