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.
Even Better Sequel: A notable example, where not only the whole game experience is completely revamped for the better, but just about everything else, be it technical, gameplay or story wise, was as well.
Fridge Brilliance: In the part of the game where you storm the palace, and when you leave the small conference room near the baron's throne room, ever wonder why you're greeted with a turret stationed outside? Simple: the Baron uses that to assassinate his rival diplomats when they leave!
Why was Jak the only person who even tried to make a direct assault on the Baron's palace, let alone be crazy enough to infiltrate it by one of its giant, dangerously high up support cables? Because he's just that obsessed with getting even with the Baron—Jak lost most of his friends and two years of his life and his innocence in a horrible world he was forced into, and his very life is at risk due to his Dark Eco corruption, all personally thanks to the Baron. And unlike the Underground who wanted to just overthrow Praxis and salvage Haven, Jak made it clear to Torn that he was in it entirely for himself and no one else, so Jak had nothing to lose—it was entirely personal to him, and as such, he was perfectly willing to go out of his way to find any chance to attack the Baron on his home turf and, at the least, get his vengeance before he eventually would have died.
Goddamned Bats: The Krimzon Guard. You do NOT want to hit one or otherwise give them cause to chase you during a mission, because they WILL fuck up your attempt. And then there are the missions where they automatically chase you...
Good Bad Bugs: A well known bug which allows the player to access and explore Sandover Village as it appears in the game's opening. This is achieved by opening the disc tray during the opening cutscene, pressing triangle, and reinserting the disc. The game will drop Jak outside Samos's Hut, complete with Metal Heads flying out of the opened rift gate. At this point Jak will be unable to move; this is easily fixed by choosing 'restart mission' from the start menu. The area fully accessible, though its surroundings only lead to bottomless voids. There has been some debate regarding the presence of Krimzon Guard crates in the village houses — some people claim that this proves the glitch was intentional, while others attribute it to the area simply being copied and pasted from the first game, with the Krimzon Guard crates automatically replacing Scout Fly Crates because of how it was coded.
The Under Port quests, especially when you reach Sig. What's especially frustrating is that if Jak's ammo reaches zero, the second part becomes Unwinnable.
That One Sidequest: If you're going for all 286 Precursor Orbs, be prepared to swear up a storm at the coliseum races. Finishing the races is difficult. Winning them takes immense patience. But to get all the orbs, you have to beat a certain time on each race, and that time is much lower than what is required for 1st place.
There's also one challenge where you have to drive all the way from one corner of the city to Torn's hideout. In less than 90 seconds. There is no room for error in this and if you keep bumping into stuff or your zoomer gets blown up (which may actually happen, since you have to drive through a crowded overpass to make it in time), you may as well restart.