Beam Me Up, Scotty!: Matador is known for saying, "I challenge you to a duel!" However, contrary to popular belief, that's not the whole sentence. The full sentence is, "I challenge you to a duel, to see which of us is truly worthy of the menorah/candelabra..." This is no longer the case in HD Remaster, which separates the line into two sentences.
Completely Different Title: The game was infamously retitled to Shin Megami Tensei: Lucifer's Call in European regions, supposedly due to a legal dispute regarding an unrelated game simply titled Nocturne (1999). Though this issue seems to be cleared, as the original name is kept in all regions for HD Remaster.
Directed by Cast Member: The Demi-fiend's English voice actor Christian La Monte was also in charge of casting and voice direction for the English dub.
Late Export for You: In addition to being the default for non-Japanese Asian versions of the game, the 2021 Steam release of HD Remaster will allow players in all regions to experience the 2003 game without the added content from the 2004 Maniax version.
Meme Acknowledgment: Atlus's official USA account used the infamous "Featuring Dante from the Devil May Cry series" when announcing the DLC for the HD re-release that would let the player see Dante.
Newbie Boom: While Atlus had attempted to bring over Shin Megami Tensei games to the west before, including the infamously bad localization of the first Persona and skipping Innocent Sin in favor of Eternal Punishment, confusing a lot of people in the process, This game in particular was popular enough to start getting the trend of Truer to text Shin Megami Tensei titles being brought to the west, culminating in the breakout popularity of Persona 3 onwards later down the line. The HD Remaster created a second boom for the game, as well as a general Newbie Boom for SMT as a whole.
Of the multiple editions of the game, only the Maniax and HD RemasterUpdated Re-releases made it out of Japan.
Raidou was removed from the HD Remaster in Korea and China due to his outfit's similarity to Japanese military uniforms used during the era the Japanese military committed various war crimes in those countries. However, Sega Asia announced that it'll see a DLC release as the "New Chronicle" pack due to some criticism from Asian-based gamers who accuse Sega (and Atlus) of pandering too much to China (or to anti-Japanese Imperialism criticism).
Posthumous Credit: Final Boss Kagutsuchi's Japanese voice actor for HD Remaster is Keiji Fujiwara, who passed away from cancer six months before the game's Japanese release.
Tomokazu Sugita and Joji Nakata reprise their respective roles as Raidou and Gouto from the 3DS remake of Soul Hackers, which in turn was a reprisal from a 2009 drama CD.
In a weird, cross-continuity example, Ray Chase reprises his role as the Tokyo subway announcer from Persona 5.
Sequel First: This was the first mainline SMT game to be released outside of Japan, hence why the III was dropped from the title for the original Western releases. And even then, it was the Updated Re-release that made the export, rather than the vanilla edition.
Working Title: The game was known as Shin Megami Tensei: Vortex during development.
Other trivia:
Dante's inclusion in the Maniax edition was thanks to a deal between Atlus and Capcom, in which the latter would allow Dante to be in the game in exchange for SMT character designer Kazuma Kaneko designing Dante and Vergil's Devil Trigger modes for Devil May Cry 3.
The reason for Angel's redesign in this game was due to her being bottomless in the original Devil Summoner design which caused problems when moved to 3D. The original plan was for her to have panties in a similar style to her top, but Kaneko instead decided on completely redesigning her outfit, leading to the BDSM themed angel of today.
and, as a Call-Back to that commercial, the HD remake trailers
