The lesson is interrupted by A Square's brother B, a clerk to President Circle, warning A to stay home during a meeting at the Senate of the Great Southern Republic.

The family prepares for another night, only to be terrified by the sudden appearance of A Sphere, CEO of Messiah, Inc, who has chosen A Square to convince Flatland about the existence of the three-dimensional Spaceland.

After rejecting A Sphere's message and attempting to kill him, the Flatland leaders execute all who have witnessed the event, except B Square, who is imprisoned for life on pain of death in exchange for his silence.

At SciFi.com, Paul Di Filippo gave the film a rating of "A", stating that it "entertains, enlightens and educates", and that "Ehlinger manages to retain the Victorian satire on pomposity and cultural blindness while updating it to modern conditions.

Dennis Schwartz (Ozus' World) gave Flatland an "A", referring to it as "smart, without being cheeky", in taking the likely unfilmable source material, and creating a "spirited avant-garde" film.

"[7]Scott Green at Ain't it Cool News called it "captivating", "an enjoyable mental amusement park ride", and "something amazingly different and intriguing to watch".

But he noted, "the complexity of the world being explored does not coherently coalesce", and that the film attacks divisive topics "with an undisciplined flurry of jabs".

"[8] Aylish Wood, reviewing in Science Fiction Film and Television, described the intertitles as fine for children, but "annoying" for adults, and found the math exposition to be "painless" but "a touch too long".

He states that the film "preserves the biting social satire of the original story with ideas and abstract violence (bleeding polygons) not appropriate for little kids (teens will be fine)".

He continues, the "film touches on current events, including allusions to the Iraq war and anti-gay prejudice, to conclude apocalyptically (the book just ends with the protagonist in prison).

Schneider points out that where A Square's experience was originally religious, the film makes it a "wow moment used to lead into some cheap gags", and states that "the story dissolves".

Schneider faults writer Tom Whalen's script for changing Abbott's story "too much", the music by Mark Slater as "sometimes apt", but at other times "a mess", the intertitle cards as "annoying", the ending for being "muddled" and trying "too hard for the relevance of 2001: A Space Odyssey", and the DVD itself for lacking a commentary track.

[11] In Mathematics in Popular Culture, Lila Marz Harper described the film as "more radical" than Flatland: The Movie, showing more biological detail, and even dreams.