GourdMovie was surprisingly great! Has a lot of great character beats, and has a fun dynamic for Hotaro and Ace where they don't really like each other for most of the movie due to their personal styles not lining up at all, but they're not actively fighting over it.
Included is the single best thing in the movie, Hotaro's reaction to Ace joking about eating a Chemy. 
Wildest part: Rinne's KR Majalde transformation needing a recharge is not in the movie at all. As far as I can tell, that first comes up in the series out of nowhere in the confusion of introducing Majalde from the movie into the series. Wild, but even more "what was even going on with the introduction of Majalde in the series being that haphazard and requiring you to see a movie?"