It's nothing that I overly enjoyed, though 'Operation Mincemeat' is a good flick.
A suitably entertaining (true, if likely 'reimagined' and all that) tale is told within roughly 128 minutes, I do think that run time could've been shorter but I wouldn't go as far as to say it drags or anything - I just felt a few moments at the end where it could've been wrapped up quicker, that's all.
Most things in this film are what you'd pretty much expect from a British production of this sort, including the cast which is full of many recognisable faces from across UK television and film. Colin Firth and Matthew Macfadyen are a pleasant pairing in the lead roles, while Kelly Macdonald leads the rest of the solid onscreen talent nicely. I also note the appearances of Johnny Flynn and Simon Russell Beale, who were both also in 2022's 'The Outfit' - a quality film, fwiw.
I could've, personally, done without the love squabble throughout, I didn't feel like it was adding anything and it wasn't exactly unpredictable. I get why it's there, given what occurs in the plot, but I wouldn't have longed for it had it not been included.
Most definitely worth a watch, all in all.