These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: The Witcher 2: Assassins of Kings
Complete Monster: Bernard Loredo is the thuggish Commandant of Flotsam who runs the town like his own personal fiefdom, running criminal enterprises and instituting racist policies against nonhumans. When Iorveth's men kill some of Loredo's, Loredo sends out his soldiers to incite riots against the innocent, nonhuman residents of Flotsam, leading to butchery and mass murder of nonhumans in the streets. Eventually, Loredo has the Scoia'tael members and their sympathizers rounded up on a prison barge which he plans on sinking instead of delivering to prison. If Geralt sides with Roche and kills Loredo, the Witcher will discover, despite Loredo's hatred of nonhumans, the Commandant imprisoned, beat and raped an elven woman for a year, eventually impregnating her. The woman was so traumatized by the events that immediately after giving birth she killed herself. Should Geralt choose to side with Iorveth and hijack the prison barge, Loredo responds by spitefully trying to burn down a building full of elven women. If Geralt chooses to save the women rather than kill Loredo, Loredo will succeed in turning traitor and selling out Flotsam to the kingdom of Kaedwen.
Game Breaker: The one from the previous game, the Igni Sign had been nerfed, but Aard and Quen (and even Axii to a point) can easily reach this level.
Bombs. You can make a load of them and just chuck them out like candies. Works especially well on bosses, even better if you brought the skill that multiplies the damage dealt by 100%. And the fact they just need two most common alchemy ingredients makes it all easier.
Heck, Igni still counts too, you just have to invest in it. With maxed spell damage enhancements and skills, hammering the sign key to machine gun out fireballs will rapidly drain the health of anything not immune to fire. If your enemy is one of the few which is fireproof, blast em' anyway- a single blast from Igni will force them into a few seconds of flinch animation, dropping their guard.
The deciding factor for most players killing or sparing Henselt is probably whether or not they can stomach the thought of him living after raping Ves and gloating about it right in front of Geralt and Roche.
The above doubles as one for Roche. Henselt just killed all of his men and raped Ves. His purpose through the game was to track down the kingslayer, only to be willing (or for some, successfully) to become one himself.
Depending on the playthrough, Loredo has a few potential moments where he may have crossed it, exactly when depends on the player. The first can be when he arranges for riots and mass murder of innocent nonhumans in Flotsam. The second can be when Geralt sides with Roche and discovers Loredo's kept an elven woman as a Sex Slave for a year. The third can be when Geralt sides with Iorveth and Loredo personally sets fire to a house full of innocent elven women just to spite the Witcher.
The heartbeat sound when you drink a Cat potion. There's a reason that mods on PC that increase potion effect longevity leave Cat alone.
Stripperiffic: Saskia's armor shows a lot of cleavage over providing protection to her heart and lungs. Potential Fridge Brilliance however, as she doesn't need the protection anyway, given that she's actually a dragon; her ability to heal is epitomised by quickly recovering from impalement at the end of chapter 3. Also, the sexy look could help sway the peasantry to her cause.