This actually isn’t neo, this show is quite literally set in 1939-40, the same year Batman as a character debuted. Most of the characters, particularly the villains, have their original golden age costumes. Harley didn’t have one, so they based her’s off the old harlequin dolls that were sold back in the day, which had the same color palette. Aside from Harley, villains were getting are Fire Bug (yes, not Firefly. Fire Bug is actually an older character, Firefly before Firefly was a thing), Two-Face, Penguin, Onomatopoeia, Clayface (red scarf), Gentleman Ghost, Nocturna (most definitely that black smoke that was possessing Alfred), Catwoman, and likely more to come. My personal favorite BTAS episode is “If You’re so Smart, Why Aren’t You Rich?” because Riddler is my favorite Batman villain and it’s imo just one of the best episodes, period.

My favorite B:TAS? "Almost Got him". Fortherecord, Selina was the onethat came the closest.