Continuity mistake: When Lilo shows Stitch her bedroom for the first time, we see a hula girl lamp on her bedside table. Then when Stitch is on the floor across the room, building "San Fransisco" out of books and toys he reaches over and drags the lamp toward him as if it had been on the floor beside him. Moments later the lamp is back on the table, and the mess is gone.
Continuity mistake: During the "bedtime" scene, Stitch finds a picture of Lilo's family. Look toward the back of the room to the left of Lilo as she scolds Stitch by saying, "Be careful of that. You don't touch this. Don't ever touch it." You can see a lei hanging on the outer corner of a painting easel. Stitch then jumps down to the floor and attacks Lilo's doll, she scolds him and Stitch rolls up to the easel and proceeds to destroy the picture on it. You can see that the lei is no longer on the easel but is now hanging on the window behind Lilo, from which she removes it and places it around his neck.
Continuity mistake: When Mr. Bubbles visits Nani's house for the second time, he first meets Stitch. Stitch, throws the book he's holding at Mr. Bubbles' head. Nani then grabs Stitch up in her arms and proceeds to apologize to Mr. Bubbles. Before she grabs him, Stitch was standing upright, just in front of and to the left of Nani. However, Nani reaches right in front of herself to grab Stitch. Nowhere does it show that Stitch moved. Also, when Nani picks Stitch up, she has him in her arms upside down, facing Mr. Bubbles. Since he was standing upright, facing Bubbles when Nani grabbed him, Stitch would not have ended up in that position.