Nothing too radical about this one, there’s just one cut, one tiny cut, and the rest of the film is the same and plays as normal. The trim in question was Helga’s reaction to Arnold holding her hand towards the end…in the original version, she plays hard to get and tells Arnold off for touching her before walking ahead of him keeping a smile to herself, with Arnold also smiling and taking the rejection in his stride.
From my understanding, this twist was done as a tease for potential future seasons where Helga would continue to hide her feelings for Arnold from her class and Arnold would have to deal with being in a secret relationship with her, but Nickelodeon passed on the opportunity for future episodes, so the ending comes off as a bit mean-spirited and confusing considering they’d both went through hell in the film and earned their romantic moment.
So yeah, all I did was remove Helga telling Arnold off, after Helga initially swoons happily at the gesture, we cut to the two catching up to Phoebe and Gerald just before Arnold’s parents ask if they can follow them to school. That’s it, the show ends with Helga content to be in a relationship with the boy she hates yet loves.