Honestly, I quite liked the movie. The parts with Moon's backstory and River felt fairly lackluster, but part of me actually likes that they were.
The show seems to be keen on giving us the chance to compare characters, and the gave us more to compare than most of the rest of the show.
Genuinely surprised how many times Marco and Moon seemed to get compared, actually.
The movie had like three scene where you could see the contrast between the two.
First we have the whole 'Aim for the Heart' thing, where Moon was told to aim for Toffee's heart but didn't, whilst Marco didn't hesitate to punch right through it when he thought Star was gone. Another is the being chained to a wall thing, where Marco tries and fails to karate chop Star free, but Moon does so without breaking a sweat. Then of course the whole Moon can't decide who she loves thing, with two obvious love interests..
Overall the show seems full of instances where it looks like the writers are trying to make the viewers compare characters. Ludo and Star on wand learning, Star and Eclipsa on power level, Toffee and Glossy on who was really in control, Jarco and Starco, the list goes on and on.
But back to the movie, whilst it wasn't perfect, I loved the way the btfo'd Toffee, and just generally revealed how much potential Marco and Star have. The two will make good rulers one day, specially given how low Moon and River have set the bar.