I see the OP's angle. In most RPGs (well, less action-oriented ones) your dodge/hit-or-miss (to name a few) is calculated on stats instead of you having to execute them by pressing buttons.

QTEs in boss fights can be annoying when you are not expecting, e.g. when you thought the fight is over and then wait, what, you have to press RMB oh crap I pressed LMB noooooo.... I was once filled with self-loathing and spite when such events occurred. But since then I have learned to adapt and survive. I think the devs were trying to add variety to the boss fights but I see they have only been partially successful depending on the player's preference.

Bosses take time to figure out so I see that as a good thing. Brute force is not always the way to go, even with maxed out Quen (well sometimes). I am just happy that Geralt is the only one who can dodge roll (sorry if that's a spoiler) 'cause that is one heck of an advantage.

Kayran: It is possible to set the trap and dodge before the tentacle hits you though. Maybe you levelled up a bit, but with Quen the damn octopus still get a fair chunk of my health off.

Potion-drinking: My view is that you should keep your potion effect up prior to main quest (I know some are just impossible to outlast the cutscene though) or if possible everywhere outside of town. There is a real sense of danger in this game. Ingredients are everywhere so you actually have a good supply of potions. Shame that drinking potions and making them take a bit of time due to clunky interface and the animations.

Letho: He does "cheat" by having infinite vigor. But heck you have dodge and he does not. So I think it balance the odds a bit. And he is not as fast as Geralt is.

there's plenty of impetus for adaption. i think most people need to have the patterns immediately apparent rather than perhaps dying a few times and then realizing it. it takes more effort and patience. again, there's been plenty mention of this game being meant for mature players, and i don't believe they just mean the story content.

OK, here it is:
Turn off Hard QTE in the game menu.

0) Have a kayran trap in the backpack, and you should have been consumed an antipoison already. If you have a kayran trap the exact spot where to put yrden is highlighted.
1) start a fight with 2 immediate barrel rolls to the left. The tentacle should miss you at this moment.
2) Run to the highlighted trap spot, face the kayran. As you reach it, another tentacle is ready to hit you, so, right after you reach the spot immediately make a barrel roll to the left and as soon as the tentacle missed run back, cast yrden, face the kayran and, as soon as you will see the tentacle is staring to stomp (wait ~1 sec), make 2 barrel rolls to the left.
3) The tentacle should be trapped at this point, chop it of, as soon as you do that run away to the "foot" of the fallen bridge in the nook and wait for a cut scene.
4) Immediately after it's over run to the same spot you cast yrden previously (it's highlighted), cast yrden, face kayran, as the tentacle started swinging motion two rolls left.
5) Chop the tentacle, run back to the "foot" of the bridge, cast quen, wait for cut scene.
6) As soon as cut scene past run to the right side. As soon as you see the green goo under your feet start rolling forward to make sure you are not caught by the goo.
7) Run to another highlighted trap spot but this time you have to click the left mouse button as soon as you'll see the hint on the bottom to install kayran trap. (if you do the trick with yrden then the kayran trap will get stuck in your inventory forever and it's heavy)
8) Face to kayran, two rolls to the left. The trap autochops the tentacle. Immediately run to the rocks behind so that kayran won't hit you in rage. Wait till Geralt jump on the tentacle (he does it automatically with QTE off) and rape the left mouse button when the hint appears (this QTE is unavoidable).
9) After you land, immediately run to the falling bridge to the left and up the bridge. Sucky part here that there are places on the bridge that are unpassable without any visible reason and initially I even thought that the bridge is not passable object. For me it works if you run slightly diagonally to to the left when you are going up till the middle part, then just forward and then diagonally right-forward. Then the cut scene kills the monster. If you stuck on the bridge without a reason, try to roll forward, sometimes it helps.

What does turning off difficult QTE do? You don't have to press spacebar?

Correct. And you don't have to click right mouse button to jump on the tentacle.

I'm playing on hard, and the boss fights are not that difficult, if you actually think a bit about what you did wrong in between each attempt. The Kayran took me a few attempts, and so did Letho. I'm not particularly l33t or anything, I thought the Letho fight was a good test.

I don't think there is a legitimate complaint here, especially if you are playing on easy or normal.

/facepalm
agreed! fucked up. Felt like, ok, WTF am I doing?

They don't call them boossfights for nothing! Improvise, adapt, overcome! If you're not up to the challenge.. then you should go and play Lego... or watch Power Rangers...

Some people like slophlong confuse the two rather often.

Ok, now I have to say wth? I have it on easy and its anything BUT easy. In fact, this is incredibly aggravating.

Can you read? they aren't saying it was hard they are saying the boss fights are poorly designed you must not be able to read since you apparently missed that entirely

i agree on the kayran boss fight but i cant see how they could have the dragon fight differently. I had great fun battling it on top of the tower, especially the tactic where it sort of goes into semi stealth mode and suddenly attacks you with the tail or tries to bite your head off depending on your position.
FYI it does try to burn you and even hit you from the sky.(just stops short of stomping Geralt)
And those of you whining over how long the fight was or how little effect your attacks have, well , its a big bloody dragon isn't it? dragonslayers aren't famous for nothing.

Huh. I actually enjoyed the boss fights in this game. They were different enough from the usual barrage of cheats that developers usually throw at me (to make the fight challenging from a gameplay perspective, at the cost of keeping the enemy true to the rules of the game world or even to the lore/story they've built up around that monster) to keep them entertaining, while at the same time actually providing me with an enemy that feels like it's worthy of being called a "monster".

That's the real flaw in fantasy games in general: the notion that you can have one man, or a small group of skilled but otherwise normal humans, coming up against and being able to defeat a freakin' kraken, or a titan, or a dragon, or any one of a dozen other creatures that should, by virtue of its power alone, be able to reduce you and the village you're standing in to a bloody pulp just by glancing at you. My weeny human, and I don't care what "level" she's at, should NOT be able to defeat something like that using conventional gameplay means, it's that simple.

Had we actually had to face the kayran "legitimately" without the scripted sequences, in order to make me feel that yes, THIS was a creature worthy of it's reputation and the build-up the game provided for it, it would have taken literally forever to whittle down the absurd number of hitpoints it would have had to have, and it probably would have had to have been so nerfed in the damage it had been able to deal that I would have been left wondering "so... what was the problem with that creature, again? Why, exactly, couldn't the village militia do what I just did?" As it was, the fight took me a little under 3 minutes from beginning to end, and it still provided me with 1) a challenge, and most importantly 2) a sense of accomplishment.

Am not overly fond of QTEs, but I don't think the mechanism turned out nearly so poorly. All in all, I'm actually rather impressed with CDPR's solution to what in my mind has been a problem in every fantasy setting ever created. The monster, even when defeated, remained as impressive as it did before I fought it. That's no mean feat in a game, and that's where I personally derive the most satisfaction. Not in building up a god-like character and stomping on everything, but in "defeating the unbeatable foe". But a corollary of that is the foe actually being undefeatable under normal circumstances, so... enter the scripts. Or the sequences. Or the Deus Ex Machinas. Or the unexpected ally. Or the QTEs.

Now, the QTE's for more mundane elements like fistfights and armwrestling... not fond of those. But for the really epic monsters? I have no problem figuring something out like that if it preserves the myth and legend and the sense of wonder surrounding these monsters. And in this instance, it did.

It's been a long, LONG time since I just paused after a fight in a game and just... caught my breath and sat there, amazed at what just happened. But that's what I did after that fight with the Kayran..

So, from me at least... the devs get full marks on that score. Yes, it had a few annoying elements to it, but I honestly can't think of how I'd make it any better than it already was, so...

Job well done in my book.

I just wonder if the reason why the Witcher.comn forums is down is because they don't want to read how horrible they screw up this game. The Witcher never managed to piss me off. The Witcher 2 did. Letho's boss fight is ludricous. For example for Riposte, why they HELL did they removed the sound clue they used in the first part?

I defeated Letho with Yrden. :D

It's too bad you guys couldn't get the same satisfaction from the multiple boss fight attempts with a -hopefully- nice victory at the end. I didn't have any qualms with the boss fight designs because I kept on trying and trying and trying and changing my strategy over and over again. I've played Demon's Souls a good chunk, so I've been battle-hardened to cope with failure and learned to adapt. XD

Especially with that Letho motha sucka. He'd just bash my face in should I try to go toe to toe for too long. So I'd hit and run and lure him to my Yrden which is GG. If he quen'd, I'd quen while keeping my distance. Then go right in. Discovering my own strategy to beat Letho made me feel quite awesome. And thank goodness I didn't need to go all the way.

Of course now I know what talents increase my vigor so on my second playthrough I have 4 sections of it before the Letho fight. Unlike last game where I only have 2 vigor up until near the end of chapter 2. More than 2 Vigor wins fights.

Yrden rules.