Continuity mistake: John enters the canal, passes by a bridge and pulls over 200 meters ahead. From his POV, the distance from the bridge is merely 50 meters. (00:35:00)
Continuity mistake: During the pool fight scene, you can see there's an orange ball next to the upper left pocket. In following shots it's no longer next to it and it has a dark ball in front.
Continuity mistake: At the steel mill, the T-1000 points his finger at Sarah and tells her to call John. The style and position of the loose hairs around her forehead change between frames.
Chosen answer: He's initially playing Missile Command, then he goes to play After Burner.
envisaged0ne