According to Josh Sawyer, several elements in the series misrepresent how Dungeons & Dragons actually works.

Stranger Things contains multiple inaccuracies when it comes to portraying Dungeons & Dragons, at least in the eyes of Josh Sawyer. The veteran designer from Obsidian Entertainment has highlighted several moments where the show diverges from the rules of the tabletop game.

One of the most notable issues is the depiction of the sorcerer class, which did not exist until the third edition released in 2000. Another example involves the Prismatic Spray spell: in the series, the purple effect causes blindness, whereas in first-edition AD&D it banishes the target to another plane. The use of the term Rogue instead of Thief is also a later addition that only became standard in subsequent editions.

Sawyer finds it surprising that a series so heavily inspired by D&D’s imagery and structure would mix elements from different editions so freely. In later seasons, the rules shown on screen are neither accurate to the first edition the characters are supposed to be playing, nor internally consistent, but instead align more closely with fifth-edition mechanics.

Drawing from his own experiences, Sawyer recalls how his early groups were relaxed about the rules before gradually adopting stricter house rules. While this approach makes sense in the first season, he argues that it feels less believable as the series progresses.

In his view, the most likely explanation is that the writers relied on fifth-edition materials rather than period-accurate AD&D rules. Sawyer believes longtime players will notice these discrepancies immediately, especially those with decades of tabletop experience.

Source: PCGamer