When I say that the movie is like the actors don't know if they are in Austin Powers or All Quiet on the Western Front, I really mean it!
From the very beginning, the movie was incredibly confused in terms of tone. To start with, it opened on the Boer War. I get it- it's a trendy historical thing to say that the Boer War was a dress rehearsal for WW1, so there is a thematic reason for it. But let's be blunt- the Kingsman franchise, while having some serious parts, was mostly fun.
The Boer War is not fun. Watching a child's mom get murdered is not fun. The action wasn't cartoony or comedic, but relatively real. And there was no signaling for how the audience should feel. Wait- do the Brits are the bad guys, because they are the ones running the concentration camp? Or the Boer sniper, because he's trying to shoot the guy running the camp?
It's a mess of an opening, with no clarity. But a moral, right? Violence is bad. Do not do violence.
But then we get what should be the central emotional conflict of the story- father who promised to not allow his son to be involved in violence (and also will not kill again), and son who wants to go solider on in glory. Except ... it's WW1, see? So we have the son go off the fight in the trenches, and gets killed in terrible fashion after learning his dad was right (no violence!). But his dad, in order to make things right, learns that ... well, you gotta go out there and kill some people. In fact, his 'catharsis' comes at the end, when he kills the main baddy by letting him fall off the Angora sheep cliff (umm ... yeah).
Oh, and the baddie? That part of the story actually seems like it could have been a good Kingsmen story. See, it's a Scotsmen who wants to free his country from the British, so he gets this complicated plan that touches on most of WW1 and history. Something so stupid it almost makes sense. Except ... it doesn't. At any level. Because, again, you're mixing the comedy (ha ha the Great War and Rasputin and Mata Hari and the assassination of Archduke Franz Ferdinand and even Lenin were all due to a desire for Scottish independence) with deadly-serious pathos (young boys getting mowed down in the WW1 trenches).
Nothing in the film works, tonally, because you can't combine zany "Rasputin loves to eat yummy cakes and have the sex and fight" scene and juxtapose it with scenes of people dying in trenches. It's too jarring, and the movie never settles on a coherent framework. Worse, the actos often appear to be in different movies, with some (like Fiennes) playing it mostly straight and other going full Austin Powers.