Game-Breaker: The Festival function. In the third game it grants Rei and Kei unlimited Spirit Power, allowing them to spam lens abilities, and gives Miku a constant Double charge, meaning she's guaranteed to deal insane damage with every shot. In the fifth game, it allows all shots to be converted into Fatal Frame shots. It's also the most difficult function to unlock, requiring the player to complete Misson Mode with the highest ranking (S for Fatal Frame III) or the game with the highest ranking on the highest difficulty (SS for Fatal Frame: Maiden of Black Water), making it mostly a Bragging Rights Reward.
Narm: The English voice acting in Fatal Frame and Maiden of Black Water is honestly terrible in places, often making it difficult to take the events seriously. Just listen to the cassette tapes found in the first game; the monotonous drag the actors perform sounds like they are giving instructions rather than documenting the horrendous, terrifying events of hauntings and sudden deaths.
Nightmare Retardant: Some of the unlockable costumes can have this effect, rendering the scare-factor null.
Older Than They Think: With the release of Pokémon GO, there was a meme floating around suggesting Fatal Frame to get the same AR mobile game treatment, with Western fans probably not realizing that an attempt has already been made in the past, although it was Japan only.
Paranoia Fuel: The games are filled with this. Especially because the player keeps walking around, expecting a ghost to pop up at any second.
Scrappy Mechanic: For the Nintendo-era games — Deep Crimson Butterfly, Mask of the Lunar Eclipse and Maiden of Black Water — the mechanic of having to press-and-hold a button to pick an item up. While the character is slowly reaching their hand out for the item and an ominous drum is played in the background, there's a chance a ghost hand will reach out and grab the character's arm, resulting in health being drained. Can lead to potential Paranoia Fuel, but ultimately fails because of the frequency of having to pick items up and being forced to watch an unnecessarily long scene of the character grabbing an item. What makes this worse is that it is literally just a flying ghost arm, clearly visible to the player. It doesn't even instigate a ghost encounter, as if an actual ghost is attacking you. It is just a disembodied arm that will drain your health and then leave.
Spiritual Licensee: Replace Proton Packs with the Camera Obscura, set it in Japan instead of America, and this series can be seen as a significantly less lighthearted Ghostbusters.
Values Dissonance: The games are very Japanese in their mind-setting and it's best shown when looking at the canon endings for several of the games. The human sacrifices are the right choice, with their death finally closing the local hellgate, and releasing the spirits of the previously deceased. This was a major annoyance with many Western players, since any Western game would've worked its hardest at trying to find another way, rather than supporting human sacrifices.
Any of the playable characters. From Miku and Rei having lost their beloved and being tormented by guilt, to Kei feeling the helplessness of wanting to save his death-seeking niece, and even to Yuuri trying to save her mentor and best friend.
Most of the antagonists count as well, since their deaths were often brought upon through no actual fault of their own. Several of them merely fell in love before their ritual, not knowing or realizing that this could end up causing the ritual to fail.
The first game
Too Cool to Live: Mafuyu Hinasaki. Presented as an amazing guy that has a pleasing personality, Mafuyu took care of his sister after their mother committed suicide. He headed into Himuro Mansion to find his professor and his colleagues, but got accosted by Kirie and lost the camera. Then he went on to explore the mansion without any weapons, was clever enough to figure out the events of the mansion's tragedy and left notes for Miku to find. In the end, Mafuyu decides to stay with Kirie at the Hellgate so that she'll never feel lonely again.