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.
Complacent Gaming Syndrome: You know that whole mall full of stuff you can use to kill zombies? Yeah, that just there for you to use until you kill Adam, take his Small Chainsaw, and triple-book it.
Demonic Spiders: The Raincoat Cult and Special Ops are this to the zombies' Goddamn Bats, the former of which appearing in path-blocking clusters and capable of knocking Frank out instantly, the latter toting machine guns, having high health, and being immune to headshots (which is the best way to take out the cultists) and both emptying Frank's inventory and dragging him off to their bases upon incapacitating him.
Frankly, any Pyschos that aren't That One Boss (we're looking at you, Convicts!) and/or The Scrappy (we're looking at you, Kent Swanson!) usually get this status - either because they are totally awesome villains, or are just the kind of people you'd "love" to beat to death with any and all weapons you can find, even the joke weapons.
Fan Nickname: Players tend to call psychopaths by epithets rather than their names. We've got the clown, the gunshop owner, the fat cop, the pyro, the shopkeeper/stooooore guy, the butcher, and the Shell-Shocked Veteran, and the Halls particularly are much more commonly called the sniper family than the Hall family.
While the game is difficult, you can get to Level 50 in no time by going to the garage right away and running over zombies constantly. Then restart the game and transfer the stats and you start the game at Level 50.
Upgrading the Small Chainsaw with all 3 upgrade books makes the game much easier than intended. You can pretty much carve your way through all but the largest zombie crowds, and boss fights end within seconds if you just charge and swing away. Escorting Survivors from point A to point B without them getting eaten or you running out on a mission time limit is still a huge pain, though.
You can perform fatalities on survivors; this has no ill effect other than knocking them to the ground for a second and possibly causing a very small amount of damage to their health. It is extremely cathartic to punch through Ronald's stomach and rip his guts out or bodyslam his head into the concrete, given how much trouble he gives you later on in the game.
Ho Yay / Foe Yay: Hinted at through Kent's alternate battle, the cutscene prior to the fight just drives the nail deeper.
Frank's covered wars, y'know? Mentioned in an achievement/trophy in Dead Rising 2 called "He's hasn't covered wars..."
Weeeeeeeeeeeeeeeeeell he ain't mah boi but the brothah is hevay~
The "Zombie Genocider" achievement, which requires you to kill 53,594 zombies (the population of Willamette) inspired Left 4 Dead to include a "Zombie Genocidest" achievement that required 53,595 zombie kills. In return, a 53,596-zombie achievement was included in Dead Rising 2 as well as Prototype,Dead Nation, and even Rock Band 3 (where guitar hammer-ons/pull-offs take the place of zombies for the achievement).
Moral Event Horizon: Carlito crossed it when he arranged for several children to carry the larva that causes zombification. Brock Mason crossed it out-of-game by attacking Santa Cabeza purely due to his Blood Knight nature.
Kent is widely hated, due to his obnoxious laugh as well as his continuous taunting. This is justified in that he is actually a psychopath. Many players don't actually know this due to killing him during the photo challenge, or from just ignoring him.
Otis. Eight words: "Don't cut me off like that! It's RUDE!" His annoying tendancy to call all the time, which leaves you defenseless and then when you drop the call, most likely because a horde of zombies are trying to rip your guts out, he berates you for not letting him finish.
The time limit, which allowed absolutely zero diversion from it, was absurdly tight and strict, and turned what was touted as a mindless zombie killing game into a frantic race from point A to point B. And it's been fully retained in the sequel. However, it can be ignored with no consequence besides shutting down the plot, allowing you to run around and goof off at your leisure. However, there's a small minority of fans who actually enjoy the aversion of the near-ubiquitous Take Your Time mechanics of most modern games.
The survivor AI, at least in the first game, routinely made Scoops hellishly frustrating. The survivors' pathfinding is usually abysmal and they sometimes decide to hang around pushing over zombies forever instead of following orders. Trying to use firearms near them is a bad idea, since a shotgun blast kills them instantly and they'll often run into your line of fire. If given a melee weapon, they'll charge off gleefully into the nearest mob of zombies and attack until they get eaten. They are, however, bizarrely competent with firearms, and can give Frank adequate backup with shotguns of their own.
The save system? You have to find specific save points, then there's only one slot per account, and if you save yourself into a corner plotwise you have no choice but to start over from the beginning (though at least you keep your stats). Also the game doesn't offer you a "quit" option when you die, only the aforementioned "delete game and restart".
Having to stand still while shooting, as the over the shoulder camera means you cannot take cover and see what you're shooting at the same time, and Frank can take pictures in first-person while walking at a respectable pace.
Stop Helping Me!: Otis' phone calls mean you cannot attack. Or jump. Or pick up items. Or hold on to large items you're already carrying. He will keep ringing until you answer. If you hang up or get hit, he will just call you right back, yell at you for hanging up on him, and start his painfully slow explanation over from the beginning. Unfortunately, answering every single one of his calls is tied to an achievement, meaning you have to go through at least one playthrough dealing with him for 100 percent completion.
That One Attack: Both of Cletus' methods of attacking are incredibly annoying to deal with. His shotgun is VERY powerful and will blast you across the room, usually giving him enough time to reload and blow you on your ass again, and he has a grapple for dealing with close range attackers where he throws you over the counter. What makes this move particularly hard to deal with is that he's bound to grab you before you can get a melee hit on him.
The Convicts. They can run you over, crack your head open or just plain pump you full of lead (even at long range). It wouldn't be so bad if you could avoid them, but early on they hang out in the most direct route back to the safe room (good luck saving people without the Wonderland Plaza shortcut). They're annoying, hard to elude, difficult to beat even at higher levels due to their erratic movements and on top of all that they respawn every day! Goddamn. At least you don't have to defeat them as far as the plot is concerned.
Isabela has a gun and fast-moving motorcycle, and is made very annoying because of two bugs: She can't be attacked directly if she is moving at all (which is nearly all the time) and you lose instantly if the game triggers a load screen - if you go into another area, if she goes into another area, if the clock hits 7:00...
Cletus. His ridiculously powerful shotgun gives you no time to move close enough to him to attack with a melee weapon or aim a ranged weapon. The only time he stops firing is when he takes a swig out of a nearby wine bottle - but he tends to only do that after he's hit you and Frank is still picking himself off the ground.. As if that weren't enough, his shotgun's spread means that it occasionally ignores the puny cover you get inside the shop itself, and he sometimes, inexplicably, gains a seventh shell if you dash out before he begins reloading.
Brock at the end is also one. You have no weapons or healing equipment, he blocks nearly every shot and his attacks are fast and hard, not to mention that he can kick you off the tank into a load of zombies. And if you fail to beat him, you have to do the tank stage again. However, if you're a high level, jump kicking repeatedly knocks his health down fairly quickly.
Jessie the resident Mega NekkoMs. Fanservice of the game here is given very little to do. Frank accidentally scares her early in the game and getting her to twist her ankle in which she gave him her gun to go help Brad. After one twisted ankle she remains mostly inactive through the rest of the game. Sure Jessie is a secondary character but so is Brad and he was quite active over the course of the game. Basically the only times Jessie does actually help you are when she once found Carlito through the Surveillance cameras and she gives you a gun early in the game (but its a mildly useful weapon and Brad gives you one when you find him anyway.) The biggest help you get from Jessie is when she is sitting next to Brad/Isabella in the little bed in the Store Room you can get a lot of Erotica points by taking pictures of her legs and ample cleavage. (Though some might be bothered by the implications behind that.) To make matters worse in the canon ending she is then quickly killed off by being turned into a Zombie. But to be fair at least she is savable in Ending B as a Survivor that gets into the copter with the others.
Some of the Pyschopaths can also be seen as this and can make one wonder why can't Frank save them like he did for Paul Carson? One example would be Kent as he may have been a cocky braggart but he does actually help you out earlier in the game and it wasn't until much later on in the game does he become a psychopath.