Starting with this episode Lisa's hair has changed from curly to straight. Her hair will be like this throughout the "Tori"-episodes.
Why does Lisa, who believes that Zack is her secret admirer, act as if this would be a big deal and that dating Zack would be something new? Only two episodes earlier do her and Zack kiss several times and tell Screech that they are going to date?
Response: It's possible that the reason for that is because in the episode where Zack and Lisa first kissed, it was a Jessie/Kelly episode, so the Tori episodes are probably a different continuity than the Jessie/Kelly episodes.
Oddly enough, the storyline with Lisa and Zack may be an attempt to tie in with episode 66.