It depends really, I just played through the game for a second time on hard difficulty, but didn't find any of the fights particularly hard. On the other hand, when I first played it years ago (damn, has it been that long?!) on normal, I remember having a harder time. The one fight that stands out the most was with the Beast, at the time my PC wasn't up to par with TW and those fires burning all around slowed me down.
I had to restart a couple of times during the other fights too, most notably the Kikimore Queen, took me ages to figure that one out. The rest I can't remember, so they couldn't have been that bad. During the second go, I expected things to be harder (I had ramped up the difficult after all), but no...not really. Again, the fight with the Beast was tricky, but this time I came prepared. After going through the game once, I had begun to appreciate the uses of potions and oils. Swallow and specter oil did the trick here nicely. However, as has been mentioned, I attribute the difficulty of the fight more to the lack of tools in your arsenal. That said, neither the Beast nor any of the other bosses required a reload. Apart from the Kiki Queen and not due to her, but because I collapsed the passage on myself
The biggest problem was the damned Coccacidium in the Swamp, a real ****** that one. Took me about 10 tries to finally get it down. Had to use Blizzard, Golden Oriole and Swallow for that one. I had the Ritual of Magic buff on me as well, hoping to use Igni to toast that beastie. The truth, however, was that only after I dropped Igni from my rotation did I succeed. While the animation lasted the Coccacidium managed to land in a hit or two on me, which often proved fatal. The same is true for other Archespores and Echinopsae (sp?) you meet early on, they can be difficult as they often manage to poison you and get in a few hits before you actually reach them. A honourable notice goes to the Alghoul, forgot his name, in the crypt in Chapter I. At that time he was just too much for my health pool, Swallow could not keep up. Luckily, Geralt is one fast bugger so I solved the problem by running around a lot. I also found it quite funny that some poor old Alghoul took me more time to take down that one of the "legendary" monsters out there.The Golem was a bit meh. I got the lighting storm but forgot to activate the obelisks, so I had to take him down the hard way. Again, it was a lengthy fight, but not difficult at all. Even with stuns, the overgrown pile of stones could not get my health down below 70%. As others mentioned, often the danger came from unexpected sources. Most often groups of enemies that overwhelmed you with numbers, such as drowners in Chapter II. That or stuff that could rack up big damage relatively quick, like Kikimore Warriors, which were always a nuisance to battle. I was a bit disappointed, however, because I went through 95% of the game without using most of the potions. Swallow and Cat were the ones I brewed most. I used Wolf once or twice, but mostly forgot about it. The famed Thunderbolt I used only once...that's right, in the very beginning. I carried three of them around, waiting for a good opportunity (I'm a bit of a skinflint in such regards...
) to use them, but it never came. White Raffard's I had to turn to a couple of times, but no more than 3. The most crucial one being in the fight with the Koschey, as it managed to get that nasty bleed on me. No oils (apart from once or twice) or bombs either and I only used Aard for most of the time, with the occasional Igni. Didn't level them up too much though, stayed at bronze talents. I should get that mod that boosts up the challenge, then I feel I'll be more worthy of voting in this poll