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.
The whole soundtrack is available for download from Bandcamp.
Complacent Gaming Syndrome: Some players have pointed out that many plants are not very good except for a small handful, like Gloom Shrooms, Tall-Nuts, Cob Cannons, Blovers, and a small number of others, considering the mere amount of strategies that could be used to play this.
This often comes more from those who've scored over 150 flags in Survival Endless as to standard play, in which they find a specific strategy and stick with it.
Averted in the New Game+, where Crazy Dave will pick 3 plants at random that you have to use.
Giga-Gargantuars are even worse. They take significantly more to kill, and have crazed red eyes. Notably, they were put into Survival: Endless because the regular ones were too easy for early play.
The Jack-in-the-Box Zombie can instantly destroy your defenses.
Zombonis. They cannot be slowed by Snow Peas and Wintermelons, nor can they be stopped by Ice-shrooms or Kernel-pults' butter. They squash all your plants in the way and they are freaking fast! To top it off, they leave an unplantable ice trail that needs to be melted with a jalapeno and said ice trail causes bobsled zombies to appear. Thankfully, Spikeweed and Spikerocks will finish them off in one hit should they run over one. And the ice disappears after a short period.
In "I, Zombie", Magnet-shrooms. They take away bucket heads, mining picks, ladders and football helmets, making many of your tougher and more expensive zombies get easily decimated. Starfruit and Threepeaters can attack other columns/rows, providing extra firepower and easily screwing up your imps should you choose to send them down a (seemingly) harmless row.
Kernel-pults, due to their random chance of throwing butter that stuns your zombies, can become these should the Random Number God choose to be nasty and cause them to constantly chuck butter. Coupled with snow peas that slow your zombies from reaching them, and you may have a nightmare on your hands.
Pole-Vault and Dolphin-Rider Zombie can be EXTREMELY infuriating. The abilities render defensive plants like Wall-Nut and Garlic useless. Take this advice, Tall-Nut is your friend.
In the second game Egypt zone, Explorer Zombies. Not very resilient, but they can one-hit-kill your plants and can be extremely dangerous if they hide behind a more resilient zombie.
In the second game Pirate zone, Barrel Zombies. Practically impossible to destroy with peas before they flatten your whole garden, capable of one-hit-killing almost all plants (except Spikeweed and Spikerock, but Spikeweed is destroyed by a single one, and Spikerock's durability is massively nerfed compared to the first game), quite fast-moving, and when the barrel finally gets destroyed, spit out three surprisingly tough Imps. In the survival game, it's usually the end once a level starts throwing them at you in large numbers.
The Disco Zombie's disco beat when he summons his backup dancers.
In the second game, the Piano Zombie's tune combines this with Oh Crap.
"Funny Aneurysm" Moment: The game was released in 2009. The Dancing Zombie originally looked like Michael Jackson. Six months after the game was released, the King of Pop died of cardiac arrest. Whoops. They ended up fixing this in a patch.
Game Breaker: In the flash version's survival, the Fume-shroom and Sun-shroom combo becomes this at night. Sprinkle the cake with Grave Busters and Wall-nuts for success and profit.
Cattails in any pool stage. It fires spikes that home in on the screen & can also pop balloons, making it easier to take Balloon Zombies down.
The Gloom-shroom/Garlic combo. The garlic diverts the zombies down to other lanes and clustered up together so that the Gloom-shroom can blast them. This can eliminate at least 75% of the zombies types in the almanac. Unfortunately, they don't stop Zombonis and Gargantuar, so keep some one-hitters and a front row of Spikerocks as buffer.
The Spikeweed/Wall Nut combo. The zombies are kept on the spikeweed by the wall-nut, and the spikeweed destroys them with minimal losses.
For even more fun, try upgrading that Spikeweed to Spikerock.
Using the Hypno-shroom on any sufficiently powerful zombie. The Football Zombie is the most tempting target, though the Dancing Zombie is even better, with the back-up dancers also turned around. And the Jack-in-the-Box Zombie would mean no longer any risk of blasting your plants, and one free explosion against the other zombies if you're lucky.
Cob Cannons in Survival: Endless. With enough of them to continuously fire at regular intervals, one can go on indefinitely. Due to this, a cobless setup is a popular Self-Imposed Challenge.
The Melon-Pult was already pretty powerful because its projectiles are worth 4 peas in terms of damage, but the Winter Melon upgrade increases the lethality by having its projectiles freeze the zombies on impact.
Within a somewhat small degree, Chompers. Sure, they take forever to digest the zombies that they eat & they are just as vulnerable as all non-defensive plants... but they recharge quickly & their bites can kill any zombie that isn't the size of a Gargantuar, even if they have the same health as a Gargantuar.
The Coconut Cannon in the sequel is a pretty good unit. It behaves somewhat like the Cob Cannon, but when tapped, it fires a powerful coconut at the zombies.
Plants Vs Zombies 2: Its About Time also gave us the plant food powerup, which enchants the power of the plant that it is used on. For example, Peashooters fire rapid pea bursts, Walnuts gain an extra layer of health & Potato Mine places 2 armed Potato Mines on 2 random tiles.
Iceberg Lettuce takes the cake. Normally it's a bomb-style plant that temporarily freezes whoever walks into it, but when you Plant-Food it, it casts freeze on every zombie on the screen, similar to Ice-shrooms from the first game. In conjunction with Bloomerangs, which shoot through stacked zombies, the final waves become useless. Both plants are available in Egypt, the first world you visit. And the best part: when you use Plant Food on an Iceberg Lettuce, it doesn't die, meaning that if one freeze wasn't enough you can just do it again.
Then you combine it with Kernel-Pult's Plant Food special, butter bombing all zombies which does stack with the freezing.
In Plants Vs. Zombies 2, Spikeweed + Wallnut + Bonk Choi = a defensive wall that damn near nothing but a large group of extra-tough zombies can get through.
The Lightning Reed. Weak on their own, but when you plant at least a whole column of them they become a nasty wave-killing machine. Especially since the lightning jumps to the closest enemy. They're also cheap and quick to replant.
Goddamned Bats: The Bungee zombie drops down and randomly steals one of your plants.
Balloon Zombies, unless you planted a Cattail or put a Cactus in each lane. Otherwise, you have to a Blover every time one shows up, or it'll float right over every defense you have. They're easy to stop, but when you're trying to get enough sun for something fairly expensive, it can get REALLY frustrating to have to keep using up 100 sun to get rid of them. Strangely enough, a group of them tends to be less dangerous than a single one for this very reason.
In the puzzle mini-game "I, Zombie" where you play as the zombies, the snow peas and kernel-pults are these. The snow peas slow down your zombies, and the kernel-pults will randomly stun them with a block of butter. Heaven help you if a kernel-pult and snow pea are in the same row, slowing and stunning your football zombie. While he's on a bed of spikeweeds.
Chicken Zombies in the second game, which are spawned by the Chicken Wrangler Zombie to Zerg Rush your plants. In Big Bad Butte, Chicken Wrangler Zombies will sometimes spawn early in a level before you have the chance to set up your defenses to deal with them.
In the second game's Pirate world, the parrot starts in whatever lanes are currently open but can then fly up or down to any plant you own and begin to steal it. During this time you have a window for your catapult plants (if you have any) to fire off a shot... and, depending on the refire rate of that plant, it might not get the shot off before the wretched bird absconds with your plant. A One-Hit-Point Wonder is still invincible if it's too fast to hit.
In the sequel, after a zombie's head gets knocked off, sometimes the Lightning Reed's attacks will magically put the head back on just for the X-Ray Sparks visual.
In Survival mode in the sequel on the Android, the game's crashing can sometimes be in the player's favor, resetting a level that's otherwise hopeless. Of course, the majority of the time the crashing results in moving onto the next level without getting a between-level reward (or worse, a Game Over in Endless mode), but at least there's a possibility of an upside.
Dolphin squeaks will make you rage during the Pool levels.
"Yeeeeeee-HAAAH!" At least the Bungee Zombies are having fun annoying you.
Porting Disaster: The sequel on the Android is prone to crashing, and certain updates rendered it completely non-functional.
Scrappy Mechanic: The fact there's no way to restart Survival mode in the sequel without dying. If you have lawnmowers but want to start all over again, you have to just wait for a zombie to kill you.
"Stop Having Fun" Guys: Mostly more from the people who've scored over 100+ on endless survival and have used specific plants tend to think that everyone else should play it according to specific strategies they used.
Squick: Brain controlled zombies turn around and eat their fellow zombies.
That One Attack: The Zomboss battle can be summed up in four words: WINNEBAGO ATTACK FREAKING SUCKS!
Although the attack is predictable (immediately after getting back up, less than half his max hp left), there's absolutely nothing you can do to stop it from insta-killing 6 of your plants.
In the sequel, Dr. Zomboss uses a similar attack (in that it's just as easily predictable) but it gets worse. You can block Zomboss with a plant food attack (this also stuns him for a few seconds) but if you just so happen to not have plant food, he could destroy two rows of your plants and then place either a lot of zombies or a gargantuar or two for a cheap victory/lawnmower fatality (Thankfully, this attack kills the zombies in the lane as well, but only if they were there beforehand). Powerups make this fight slightly easier (perhaps EA made Popcap create these boss fights to get players to pay up for better plants and powerups...).
Stage 4-10. The stage is in complete darkness in which you cannot see your plants or the incoming zombies until lightning illuminates the lawn for a few seconds. It is also a conveyor level. You'll get to unlock the Yeti Zombie the second time you play it, though.
Same thing for level 5-5, which is where you're fighting against oncoming waves of bungee zombies relying on nothing but Chompers, Pumpkins, Flower Pots, and Cherry Bombs. Crazy Dave sums it up at the start of the level.
Crazy Dave: You're gonna hate this level. It's one bungee zombie after another. I hate those bungee zombies. With a passion. And a vengeance. Here come those idiots now.
The "Survival - Fog (Hard)" level. "Hard" is a MASSIVE understatement. The fog levels are among the hardest in the game to begin with, but this one takes it Up to Eleven and beyond. If you pick your nighttime plants well, you can actually get fairly smoothly through the first six flags... but then the game will (as in, 100% guarantee — it's part of the level design!) send a few Gargantuars your way for flags 7 and 8, who will not hesitate to flatten your entire carefully-prepared yard without blinking an eye. The final waves become largely a Luck-Based Mission based on how many of of your plants are alive.
"Column Like You See 'Em" and "Bobsled Bonanza" are two difficult mini-games that mostly rely on luck. The former gives you plants on a conveyor belt, and will only give you Flower Pots and Pumpkins right when the waves of Gargantuars start swarming you. The latter can ruin you by sending you several bobsled teams before you set up anything that can kill them. The former overlaps with That One Achievement when attempting to beat it without using Jalapenos.
The "Big Bad Butte" challenge level in the Wild West zone in the second game has a nasty habit of hitting you with powerful zombie types right from the start, before you have a wide range of plants to choose from. If you aren't lucky enough to get a powerful plant or two in the random selections, you're doomed.
The sequel being free-to-play and having certain features require payment. Electronic Arts, perhaps the king of this practice, publishing the game certainly doesn't help.
Then the December 2013 update for the second game ended the need to use keys to access certain levels, which pissed off all the people who'd used real money to buy keys.
And the February 2014 update made things even worse, with the change to having lost lawnmowers in the challenge levels disappear permanently unless you bought them back leading to accusations of "Allegedly Free Game!".
The Woobie: The Wall-Nut starts off looking more than happy to protect the lives of its planter and comrades, but when the zombies begin to devour him and his smile slowly disappears, you can't help but feel sorry for him.
A single tear begins to stream down Tall-Nut's face when he gets near the end of his health. Apparently the game's composer and a few beta testers would protect Tall-Nut with a Pumpkin because the tear made them feel bad for poor Tall-Nut.
Although the Tall-Nut tear is more of a manly tear.
The Garlic starts off looking happy and care-free, but when he's near the end of his health, he gets big tear-filled eyes...