Graham Chapman's story, frankly, is better served by his Wikipedia page.
Stream A Liar's Autobiography: The Untrue Story of Monty Python's Graham Chapman
What are people saying?
What are critics saying?
New York Daily News by Joe Neumaier
John Cleese, Michael Palin and Chapman himself (courtesy of interviews, skits and various recordings he made before his death from cancer in 1989) chime in. It's an odd little trip, but if it weren't, one would have to ask, "Well what's all this, then?"
A coda shifts to video footage of Cleese's irreverent eulogy; you wish the whole film could have been as slyly somber. It's what the colonel would have insisted upon.
Like a lesser Python entry ("The Meaning of Life"?), it's alternately brilliant and frustrating.
The New York Times by Manohla Dargis
It's a colorful patchwork of family high and low points, schoolboy days, professional triumphs and assorted epiphanies (including sex with women followed by sex with men).
Portland Oregonian by Marc Mohan
Unfortunately, it just doesn't come together. The animation ranges from crude approximations of Terry Gilliam's cutout style to borderline puerility, and the entire enterprise strives far too desperately for the sort of irreverence that Chapman could conjure with a cock of his pipe-clenching head.
What's missing from this movie is any of that sense of what made Chapman so important, or why he was so often at the center of Monty Python's best skits and movies, up until his death from cancer at 48.
Entertainment Weekly by Owen Gleiberman
It's like watching "Yellow Submarine" laid over a celebrity-therapy episode of Dr. Phil.