- The game's universe as a whole is very bleak. Branaic has footholds in both Gotham and Metropolis and other locations aren't much better. Khandaq is in ruins and full of zombies, Bludhaven is freshly nuked, Smallville is under assault by Doomsday clones, Toyman has taken over Styker's Island prison, Oolong Island is besieged by its own creations...it's all terrifying.
- The Eldritch Location Trigon's power has turned Gotham's park into. There's pillars covered in demonic power crystals just floating in the air hundres of feet up in odd formations and some parts of the ground look like hell itself.
- Toyman's takeover of Stryker's Island involves creepy robot dolls. Including giant ones.
- Playing in the Arkham Asylum Alert can be quite creepy and the voice that sometimes blends in doesn't help either.
- Ace Chemicals is eerie too, and there you have Morrow over the PA system, constantly screaming for security to stop and/or kill you.
- Oolong Island. You don't know what, but something has gone wrong on this secret test island for villains. The sunny tropics do not make the attacking robots and screaming scientists less creepy.
- Ellsworth Memorial Hospital: fleshy red globs dangling from the ceilings. Mind-controlled doctors and patients indulging in the worst impulses the Seven Deadly Sins can bring out of them, under the watchful eyes of demonic overseers. Random altars full of blood (take a guess where it came from). Piles of unidentifiable flesh with giant eyeballs that are constantly looking around and blinking, as if panicked about what they are now. Have a nice day.
- All those Exobytes are from future versions of the League and Legion. They have infected thousands of people, enough that there's a hospital full of experimented-on NPCs, and Power Girl giving speeches at the university on how to use your new powers responsibly. And there's nothing saying a single people has one set of Exobytes or that they stick to their original's alignment. So let's put together a scenario: Kryptonian Exobytes mixed with Joker Exobytes infect an arsonist in prison, producing a superpowered firebug essentially trained by Superman and the Joker. And his powers are still growing...
- In play, one of the first missions that Lex Luthor puts his prodigies to is to infect university students with a mutagen which turns them into junior versions of the Parasite, with no indication that long term infection can be cured. Per the entry for Deadpan Snarker, Calculator sarcastically comments that there's no way he can see that going wrong, and that's without considering the welfare of the students (because Calculator, Luthor, and the player villain certainly don't). He later combines the Parasite DNA with Doomsday DNA and lets it loose in Smallville KS.
- Lex really gets his Mad Scientist on in this game. It's terrifying, as are some of his employees like Dr. Psycho.
- As said in the YMMV page, the player character is quite possibly a total villain. Some of the villain missions are pretty messed up for a T-rated game, including: car-bombing police, lighting injured police officers on fire, summoning demons, giving people lethal doses of venom (which is shown to be a visibly painful way to die), poisoning drugs, knocking random people off of tall buildings (killing them)...the list goes on. Worse is that your body-count will also likely include various DC superheroes (ok, they're usually not killed, but still).
- One sidequest of the Revival of Isis story arc has you defuse Joker Venom from a break-in a few days back, inside a warehouse filled with zombies. The very last one is in a hidden back room that has more in common with the Joker Missions than the current one. And then you see the Zombie Joker Goons.
- The way to the room is indicated by a red arrow painted on the floor... and it's very easy to mistake it for something other than paint.
- In Metropolis, heroic characters are often tasked with saving citizens before they turn into apes, fish men, or some other suitably Silver Age chicanery. In Gotham, when dealing with the Joker? Victims are strapped to huge blocks of C4 with a timer where your failure means their death, end of story.
- Not that the Metopolis guys have it any easier. Getting turned into gorillas or beastmen usually is accompanied by terrified screams of pain. It's worse with the gorillas, since as soon as they turn Grodd's mind control kicks in and they instantly calm down with a "Hail Grodd!"
- Black Lanterns are coming to the game. You know all that wonderful nightmare fuel from the comics? From raising the dead into Black Lanterns, to possession by a Black Lantern Ring? Its now in the game with visuals and audio to match. Sleep tight!
- The Anti-Monitor's Shadow Demons. All black humanoids with weird, unnatural, janky movements (likely lag due to the sheer number of characters on screen at the time).
Nightmare Fuel / DC Universe Online