Factual error: As a trash compactor Wall-E does not function logically. When he fills his chest compartment with garbage and runs his internal compactor, the cube that exits his body is the same volume as the trash he puts in, despite that trash having been compacted. He does not add extra trash to fill the empty space after running the compactor - there are three scenes that show him filling up only once with loose garbage and then ejecting a densely compacted cube. (00:02:30)
Continuity mistake: After the escape pod scene (but before the 'dance'), Wall-E uses a fire extinguisher to fly back and forth. Between every camera shot except one, all the extinguisher particles disappear instantly. (00:56:50)
Continuity mistake: When Eve fires a shot at the tanker they show an overhead view of the scene - there are three other tankers sitting on the starboard side of the exploded tanker. When the tankers fall like dominoes there are now four of them next to the exploded tanker.
Character mistake: Captain McCrea tells the passengers that it's the 700th anniversary of the Axiom's first flight. The Axiom has been in flight for 255,642 days. Actually, 700 years is 255,675 days. That figure includes the additional day in 175 leap years.