Continuity mistake: In the scene where Seth Rogan says, "Is that the Six Million Dollar Man's boss?" and points to the Oscar Goldman doll, the doll in blue to the right of it doesn't have a hat on. In the scenes immediately before and after, it does.
Continuity mistake: There is a shot of Trish's hand on Andy's shoulder and her other one in her lap when they are talking about selling his action figures on eBay. The camera switches to an over-the-shoulder shot of her and both hands are in her lap. The view switches instantly, so there's no time for her to move her hand.
Other mistake: When Andy first meets Trish, they are looking at a display of DVD players and VCRs. She points to a DVD player and says "This one looks pretty good." Andy replies, "You don't want that VCR." Although a display card has been deliberately placed in front of it to mask what it really is, the VCR appears to really be a DVD player.