The Origin of the Silver Surfer: Part 1 - S1-E1
Continuity mistake: When Uatu the Watcher is speaking to the citizens of Zenn-La, some shots show the Kree emissary standing in front of the Skrull emissary, while other shots show vice-versa.
Buttercrush / Fuzzy Logic - S1-E4
Continuity mistake: When Buttercup punches a hole in the wall to see her sisters are being lowered into lava, the hole's initially quite small. In the next shot, the hole is noticeably bigger.