There were a lot of great moments in the movie, I love that Vasquez held onto a good amount of his humor as the years have wore on, I'm sure many things have changed for him as has the world & culture around him, so it inspires me to see the unique expression of all the bizarreness & absurdity in a time that has largely departed from this style of humor & show.
I enjoyed the movie & I would recommend it, it really punches you in the nostalgia bags & gives a lot of good laughs.
I only have a few small gripes about the movie, having been a huge fan of the original series.
The movie departs a bit from the vibes of the original series, for whatever reason. For one, the movie exhibited a lighter atmosphere, I understand that perhaps the production assumed that the audience has changed and was afraid to alienate their audience, but Invader Zim was great in large part because its irreverence, many great art pieces are great because they're bold & actually defy people's expectations. There was never a good comedian who only said what was socially acceptable, and that's why it brings me some sense of sorrow to see Zim made less intense, diminishing near the first point of contention, even Dib & his family having obscenely 'normal' moments. Gaz is not someone pretending not to care about her brother, being annoyed with him, & looking for ways to injure him, but in the movie she is, and Dib's dad doesn't really care that much about him, he's actually consumed by his passion for science to a fault, except in the movie.
The power & intensity of the individuals are diminished in the movie, the nature of their reality is toned down perhaps to tailor to more modern audiences, there is less darkness & ugliness, less witty, repulsive, absurd, nihilistic, subtle commentary, & more silly, apprehensive humor that pulls too many punches.
I would gladly watch a remake because I still love the humor when it hits right & the remnants of the original atmosphere they kept, but that doesn't change the fact that the movie could have been better if it was significantly more authentic & daring.