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: Sly 2: Band Of Thieves
Breather Boss: Compared to the other bosses, The Contessa is a piece of cake. Her attacks are all slow, weak and pretty easily dodged. Even after she starts using the Clockwerk eyes on you, it's quite possible to end the fight without taking a single hit.
Family-Unfriendly Death: Arpeggio. After Neyla betrays him and possesses Clockwerk, she quickly proceeds to point a laser at him and utterly destroy him, leaving behind nothing but a puff of feathers and his monocle.
Foe Yay: Carmelita and the Contessa have a bit of this in "A Tangled Web".
Narm: Neyla's alleged English accent. It's supposed to be a Cockney accent gained during her time educated in London (she's actually Indian) but it's rather glaringly fake. Probably a case of Ooh, Me Accent's Slipping, as her accent sometimes sounds Australian.
Moral Event Horizon: Neyla crosses it when she betrays and kills Arpeggio and possesses Clockwerk, becoming Clock-La. If the betrayal to the Cooper Gang and Carmelita at the end of Episode 4 was not considered crossing the MEH, this is it.
Player Punch: Bentley being crushed by Clock-La's closing beak and rendering him in a wheelchair; particularly because the last action you get to do before the ending cutscenes is getting Bentley to grab the Hate Chip. No matter how hard you mash the buttons as Murray, it's all in vain. Made worse when Bentley tearfully cries, "Pick me up! I can't walk!"
That One Boss: Rajan, who has absolutely massive health (even though you are playing as Murray, your attacks still do little damage to him), has damaging attacks (which are also hard to avoid due to Murray's size and slow speed), and summons goons to help him fight which also do a lot of damage if they hit you.
The Water Bug mission in Episode 3. Once you know where all the pools of water are, it's a lot easier but it essentially turns the jungle into a maze for first time players.
The Contessa's levels (Episode 4 and Episode 5) are a real pain-in-the-neck. You spend the first three missions as weak techno-wizard Bentley — before you can spring Sly. With the exception of getting Murray out, Sly's missions are long and painful. At least the Operation: Trojan Tank is not as Nintendo Hard as the rest of the level.
Charged TNT Run. Not only you have to go to three different areas to collect certain objects, you are unable to fight the guards. And often, if you have to drop in front of one, there's a chance that he will never move, meaning if you move, game over.
Even if you don't move, if the guard touches you, they instantly detect you and attack.