First off, I love the concept and direction here. I'm sure your instructor was impressed! Totally reminds me of Digigirl Pop and Super Milk Chan.
My issues though (and I'm sure that since this was just for an assignment that it's not too big of a deal) -
The cut to the tagline & tv ad feels abrupt and the tv ad feels a bit out of place here. I do love the funny text and 3D model but it would probably feel more in place if the ad itself was Y2K-y as well.
Other than that, the characters are cute but I feel like the character design could be strengthened. The main character especially feels off with how heavy the detail is on their head and shoes but not body- maybe finding a middle ground by simplifying the antennae/eyes would do it while leaving the shoes detailed would help the character feel concise while helping the shoes stand out.
I do feel that the rock monster is lacking but, seeing as this was a student project, I assume you weren't too concerned with it. Y2K designs are always super fun though and I encourage you to keep playing with them!
Everything said though, I do love your project and it makes me happy to see a fellow designer work in a Y2K style. Keep it up :)