Although this is a continuation of the series' final cliff hanger, the scene where Susan and Emily are poisoned, and the scene where Cathy tells Matt about it, are completely different.
In the series' finale, George is promoted to Detective Two, and Matt complains that George has only been on Earth for 6 years and doesn't deserve the promotion yet. But now throughout this film, they comment that they've been here for 5 years.
When George and Matt are singing to Susan in the hospital, you can clearly see Matt trying to stifle a laugh several times.
This movie ignores the plot of the TV series finale in which two Newcomers had already died from the virus that infect Susan and Emily, and that the police were already aware of the virus.
When Ahpossno is getting ready to leave the spaceship, the commander erases his Overseer tattoo. But when he arrives on Earth and sees the homeless Newcomer, Ahpossno show his tattoo.