* AnticlimaxBoss: Lucifuge in the first BonusDungeon. You'll be expecting a tough fight, given that he's the second-to-last boss in the dungeon, is one of the only opponents in the game who can act twice in one turn, and can use both Tetrakarn and Makarakarn. Unfortunately for him, he only has five moves, those being the two -karns, his basic attack, an inaccurate paralysis-causing move, and Demon Birth Cry, a weak Almighty move. He has no elemental attacks, and thus no way of hitting weaknesses, and no way of canceling buffs and de-buffs. If you buff your Endurance and Magic to the max and unload with Almighty, there's literally nothing he can do to you. The most trouble you're likely to have with him is if the paralysis move connects on your healer.
* ComplacentGamingSyndrome: Sure, you can use all of your demons abilities and have the main character attack. But as soon as Nemissa gets her [[HerdHittingAttack ma- level spell]] and you keep putting points into her magic stat, she does so much damage there's not much reason to use anyone else besides upping your demons' loyalty[[note]]which can be done just as easily by using some sake to change their personality and have them just Guard[[/note]] and the occasional enemy who's immune to Nemissa's element. And once she gets the Megido spell? Then all you really have to worry about are a few bosses and the loyalty of your demons.
* CompleteMonster: [[BigBad Kadokura]] is the [[CorruptCorporateExecutive CEO of technology giant [=AlgonSoft=]]] and one of the most influential men in Japan. Though [[VillainWithGoodPublicity beloved by the public]] for his useful products and philanthropy, this masquerade hides a twisted man devoted to [[TakeOverTheWorld world domination]]. Prior to the start of the story, Kadokura had discovered Manitou, [[TopGod supreme god of the Native Americans]], and decided to use his power for his own ends. Kadokura founds Amami City, a state-of-the art seaside metropolis, and Paradigm X, a totally-virtual city that can be accessed by Amami's computers, as an excuse to get millions of people into one place to [[YourSoulIsMine sacrifice their souls to Manitou]]; the chips that run the virtual city are infused with demonic power, sending the souls of the players via cyberspace to feed the sleeping god. By the end of the game, most of the city's population has had their souls removed. When he meets the heroes for the first time, he falsely blames the entire EvilPlan on his demon partners Azazel and Satanael, then after the heroes kill them he thanks them for saving him the trouble of doing it himself. When the heroes finally corner him, he swallows a number of souls himself to [[OneWingedAngel power himself up]]. Willing to exploit everyone from ordinary citizens to a creator god, Kadokura has no place in his heart for anything other than [[ItsAllAboutMe his own rise to the top]].
* DemonicSpiders: ''Anything'' with spells that can inflict instant death, mainly due to the main character lacking innate resistance against them and his death meaning that the game is over. And in a lot of cases, if you run into an enemy group where one enemy carries Hama, they all do. ''And'', unlike later entries in the series, Hama and Mudo spells will always hit ''your entire party''.
* EvilIsSexy: Nemissa, depending as much on your definition of [[AntiHero evil]] as on your definition of sexy.
** What is arguably her strongest skill set requires that you refer to Hitomi as sexy.
** Kadokura to some.
* GameBreaker: Once you reach level 59, you can fuse Kartikeya. At first, he seems unremarkable aside from his high speed stat, but if you can fuse him with Tetrakarn and Makarakarn, then you'll find that you have created a demon who can and will protect your entire party from nearly all damage. Because of Kartikeya's speed, he will most often move first, and wise casting of Tetra/Makarakarn depending on the situation, combined with those spells lasting the entire turn instead of for just one attack like in other SMT games, will prevent your team from going down. However, you still need to get his Loyalty up, and of course neither spell works against Almighty spells, but he is still a valuable asset that one would be able to keep for the rest of the game and even into the extra dungeons because of his utility.
* MostAnnoyingSound: Voice acted menu prompts in the shops. Especially annoying is the "announcement" voice in Paradigm X's forums. The translators opted not to voice minor [=NPCs=], which includes the people inside the forums. But for some reason they left in the announcement voice. It doesn't make any sense for there to be a voice out of nowhere asking which person in a room you want to talk to. But it's there nonetheless. Fortunately there's nothing useful to do in the forums and anyone who wants to hear what the [=NPCs=] have to say can turn the voice acting off first.
** Eat Whole, a favorite of [[VillainousGlutton gluttonous demons]] such as Ammuts and Peallaidhs. This is the strongest "Skill" element move in the game, with a whopping 60 base power, and it hits the entire party for damage. Even worse, there is no armor in the game that resists Skill damage, and many of the demons that have it are immune to electricity, largely shutting down the best Nemissa build.
** King Frost's Self-destruct attack, which he uses once he runs out of HP and can easily bring you from full health to zero. If the protagonist doesn't have enough HP to survive it, or is too slow to guard before King Frost uses it, you're screwed.
** Meat Bullet, a rare instance of a mutual HPToOne attack. If the main character is hit by this attack, you are [[CriticalExistenceFailure one hit away]] from an instant [[WeCannotGoOnWithoutYou game over]]. Especially bad cases are Tuo Fei, who is so fast that you can die before doing anything, and the Romero fight that can have three to five Rolwoys, all capable of using this move.
* ThatOneBoss: Mayone. She appears nearly right after you finish the mansion level. She packs a full team of five demons; one of them a Purple Mirror that will discourage you from using spells till you break it, many of them like flinging spells your way, and she has Mudola to cheap-kill the main character and anybody else in any row she targets but his survival is key. Either you equip yourself with anti-Death armor, have a fast-enough demon with Makarakarn to nullify nearly all blows and Mudola, or have a lot of luck. It doesn't help you need to see a cutscene before you're forced to fight her.
** Shemyaza. He likes flinging way too many [=AoE=] spells (Mabufula, Mazionga, and Maragion) your way, especially Megidola. His Delta Pulpulae inflicts confusion on all party members, and things will get worse if your demons happen to drop out. If you lose to him, you'll need to watch a three-minute long cutscene + dialogue.
* ScrappyMechanic: The Loyalty system, which requires you to give orders to demons in battle that suit their personalities or risk them becoming less effective in battle, disobeying, or even leaving. It's especially annoying when it comes to demons whose loyalty can only be raised by letting them do whatever they want in battle (like, say, you have a demon who likes to sacrifice itself to restore your party, even when there's no need to do so). To be fair, the game does offer the player a few ways to tweak this, either by buying special items to raise loyalty or change demon personalities and by having demons whose loyalty is maxed out follow orders, but it is telling that one NPC you encounter in Amami Airport will tell you that it's a "pain."
* SeinfeldIsUnfunny: A lot of the things that are hyped as revolutionary aren't particularly noteworthy nowadays, with a lot of them being impractical or needlessly complicated. Even by the time the 3DS version was released, little of it would be seen as anything more than a gimmick.
* ThatOneLevel: The Amami Monolith requires an absurd amount of backtracking compared to other dungeons across a huge swath of space, all with a high encounter rate with powerful demons with annoying resistances, including one that can ''de-level the party''. The final dungeon is a cakewalk in comparison.