It's interesting to look at 'Between Two Ferns' as an example of how shortform comedy can often sometimes exist in its own bubble.
American sketch comedy - whether it's the experimental stuff like 'Tim & Eric Awesome Show Great Job' and the more recent 'I Think You Should Leave', or the obvious stuff like 'SNL' - is decidedly hit and miss. You can take any of those examples and there will be a wealth of excellent, memorable sketches and complete duds.
Curiously, 'Between Two Ferns' in its twenty-episode run on Funny Or Die had a 100% hit-rate, with each sketch as perfectly balanced and excruciatingly funny as you could get out of the concept. All of this wasn't just down to the game celebrities who turned up for Zach Galifinakis as it was he himself drawing it out of them.
As a concept, the movie only holds water when you realise it's essentially a vehicle to get him in front of celebrities, meaning that anything outside of it - the supporting cast of Lauren Lupkus, Ryan Gaul and Jiavani Linayao - aren't all that necessary to it. Yet, without them, it wouldn't work and it'd just be a series of interviews tied together for no apparent reason. Still, it works despite itself and when the interviews do start to happen, they're as funny as anything Galifinakis has ever done.
The icy humour from Galifinakis' humour does somewhat lose its effectiveness when it's presented one after the other, and you get the sense that even he himself recognises that it's being pushed on a little bit too long for his own good. Yet, with a runtime of just over an hour and twenty-two minutes, it works perfectly for something on Netflix.
Each of the celebrity guests - Paul Rudd, Benedict Cumberbatch, Tiffany Haddish, Keanu Reeves, David Letterman - they're all as funny as you'd expect in the setting, and Galifinakis wrings as much humour as he can out of them. That said, an extended subplot with Chrissy Teigen and John Legend is one of the few examples of the movie failing rather than working for the concept. It's a shame, but thankfully, it resolves itself quickly and moves on from it.
If this is to be the end of 'Between Two Ferns' as a going concern, it's probably the best way it can go out. It's weird, it's funny, it's by no means anything more than what it thinks it is, and the very fact of its existence shows just how good Zach Galifinakis is as a comedic performer.