Other mistake: In first episode Wells apologizes for locking up Clarke's dad, then acts surprised when she tells him he got executed, when in episode 3 it's revealed they both assisted in the execution.
The 100 (2014)
1 other mistake - chronological order
Starring: Eliza Taylor, Paige Turco, Marie Avgeropoulos, Thomas McDonell
Continuity mistake: At the beginning of the episode as Clarke is walking towards the window in the door, her right arm is already injured, but she doesn't actually get that injury until she breaks the window and reaches through the glass, which cuts her right arm.
Earth Skills - S1-E2
Clarke: Follow me.
Bellamy: And why would I do that?
Clarke: Because you want them to follow you. And right now they're thinking only one of us is scared.