* ComplacentGamingSyndrome: Averted due to the experience system detailed above. If you keep using a mastered item, you're missing out on EXP and slowing your leveling to a crawl. You have to constantly switch equipment to continue levelling up.
* DemonicSpiders: Monstrosities in general. High health and nasty attack patterns which deal very high damage and cannot be parried.
** [[UpToEleven Especially]] in the [[NintendoHard negative rebirths]], where there could be some nasty compulsory XP bonuses mashed into a monstrosity like 'Do 20 scratches', 'Kill Titan with scratch',... Good luck.
* GameBreaker: Heal magic can be this, particularly with the last magic ring as it gives you full health and can recharge several times in the course of one fight. Then again, considering the requirements to get it, it can also be considered as BraggingRightsReward.
** [[spoiler:Discover Bloodline -1, and you will gain the strongest set of equipment, able to far outstrip ''even the Infinity Blade itself''. You will smile with glee when you get to strike down the God King in mere seconds!]]
** In II with the Vault of Tears expansion, the Holy Band is definitely this. It does 10000 irresistible holy damage that can also heal you the same amount as the damage being done.
** Alchemy in III brings us the Rare Health Potion: cheap to make (two blue berries and two butterflies), only 5 minutes to cook, and restores 250 health ''per second''. There are very few enemies capable of matching this output in damage on you, making most fights trivial.
*** It only gets more hideously broken when you acquire Siris' Potion Master skill, which not only multiplies the effects of any potion by ten, it also lets you carry over ''triple'' the amount of potions. Apply this to Rare Health Potion, and you're getting ''2500'' health a second, and can basically fill your potion inventory with them.
* GoodBadBugs: You can retry the fights against the bosses by exiting the game and killing the app before they run you through. Has never been fixed, likely due to the outcry it would cause.
*** Averted in the case of fighting The Collector and the Deathless quests. Killing the app in the middle of the fights will have the game treat it as if you lost the battles and you will find that your items have been taken from you upon reloading the app.
* SuspiciouslySimilarSong: The music that plays during the [[spoiler:Ryth]] fight is one of [[StarWars Duel of Fates]]. [[ShoutOut It's pretty easy]] [[LaserBlade to see why.]]
* ThatOneAttack: The God King's Fury attack can very well end a Bloodline then and there. It's tricky to parry, very difficult to dodge, and is capable of tearing through your entire health bar. It gets even worse in the final round, when he starts using it every other attack pattern.
** Ryth also has many obnoxious attacks that do absurd damage. One of his attacks has him slash in both directions at the same time and can only be blocked and eats a ton of shield points to boot. It's also fairly fast so you may not see it coming. However, he also has THREE fury chains to deal with and each one will kill you on the spot if every attack in the chain connects. His first fury chain is confusing and cannot be dodged without dual weapons. He jumps into a mid-air barrel roll, kicking the player several times. After landing, he stabs the player and continues to spin around and swipe to the player's right. The second is very deceitful due to his very fast speed in his kick. After kicking, he stabs the player. This is followed by a diagonal slash from the upper right corner of the screen. His third fury chain is a back-flip followed by a front-flip in which Ryth slashes down at you. He proceeds to slash upwards, to the player's left, and again out of the upper left corner. You have to hope that he doesn't get many opportunities to use these chains or you'll be doing a lot of retrys.
* ThatOneBoss: The God King is an intentional example of this trope. His lethal powers cause the entire storyline. He starts at level fifty when the player is level one. Every time the player beats him, he goes up another fifty levels.
** The sequel has a few of these, naturally, though the one that takes the cake is the Bog Giant, the tree trunk horror with the Vile Blade stuck in it that comes with the "Vault of Tears" expansion -- thankfully, you can restart the fight if you die like a regular encounter. But it is horrifyingly fast for something so huge (you will need to get used to its speed to dodge and parry properly), has new attacks that can catch you off-guard, and when felled, it goes OneWingedAngel and transforms into the Moss Golem, a Monstrosity that will give you a hard time even if you mastered fighting the first form. Buffs used in the first battle will disappear at the subsequent battle and ''there is no break between them''. However, you will be rewarded with a sword that rivals the Infinity Blade in attack power after that.
** The third game has Therin. He uses the same BladeOnAStick style as the Fel Siren, an enemy considered to have one of the harder attack patterns to fight against... only Therin likes to do a lot of feints, tricking you into doing the wrong counter all the time.
** Also in the third game is Ryth. He's always overleveled to the point that one slash will kill you, and your gems and potions are rendered useless against him. You also have to use a Light weapon the first time you fight him - one of his attacks can only be blocked, so he'll take out your shield very quickly.
** Again in the third game, we have The Collector added in by the Blade Masters update. He's level 500 the first time you encounter him in the Crevasse and his battle mechanics are what makes it such a pain to fight him. To fight him, you must be willing to risk whatever weapon you currently have out and you will lose it if he defeats you, but you will win his weapon if you defeat him. And just like the Deathless Quests, you can only win your weapon back by hoping that you run into him again and beat him as well. If you lost a powerful weapon to him, (which is highly likely because of his massive health pool) his damage output increases drastically the next encounter you have with him. In fact, he always deals high damage because of the rare weapons he uses on you. Adding to the horror, his fighting style is randomized every time depending on what weapon he's holding. And talk about a damage sponge as well! To put things in perspective, the second time you fight him, he's level 2500 and has 200,000 hitpoints! That's twice as much as the dragon Ba'el! If you don't start using Rare Health Potions at this point or have a good Heal ring, you have no chance of defeating him. The only saving grace is that he won't switch fighting styles during the fight. ThatOneBoss indeed!