I struggle to really think of any way in which the film could have been better. The direction and cinematography are on point; the cast are wonderful; and the plot unravels neatly, keeping you guessing but never completely confused. That said, there were some minor irritations and one fairly large letdown. First, the animals in the film are weird (and not great CGI either). Crocodiles do not leap out of the water at ibis; fish do not suddenly attack a resting object. Second, the final double suicide/murder was a neat ending, but even someone like me with no understanding of firearms can predict that a .22 gun would struggle to go through two people, and anyone with any sense of anatomy would see that the trajectory would likely lead to a long, painful death (and possibly one that could be prevented, considering the multiple doctors onboard), not the swift, elegant droop. As I say, these are small irritations that I can largely ignore.
The bigger letdown is that the ending just felt a tad anticlimactic. I suspected the husband very early, mainly because he is so clearly in love with the "jilted" ex and the time spans just don't make that much sense. I began to consider that they were working together when the ex just showed Poirot her gun and intentions, which felt off; plus it wasn't clear how she kept catching them up. The twist cover-up in the middle was a nice touch and meant that I stopped suspecting them both long enough, but then it made the final reveal feel a little cheap. It was a clever ploy and well-executed, but I think the irritation is that their motive is never clear. He just wanted to be rich? But they'd landed him an excellent, well-paid job. And what would have happened if he hadn't been able to seduce the heiress or if she'd actually been a good friend? It just... it didn't really add up to motive for multiple homicide 🤷♀️
That said, I still thoroughly enjoyed myself. The locations are stunning, the story well-paced, and how can you not love this cast? Russell Brand playing a loser! Dawn and French playing upper-class lesbians! Letitia Wright being a goddamn badass, but with flair and social intelligence, rather than simply being a genius and action hero 😉 Gal Gadot actually getting to show some real range of emotion (and doing so impressively well; she's phenomenal in this)! And, of course, Branaugh is a really solid Poirot. Even my initial irritation at the prelude backstory to his moustache ended up being a meaningful inclusion and redeeming itself. I know they changed a few things from the book, but I feel like the ending is probably something they were largely stuck with, and so I guess my one main criticism can be levelled back at the source, rather than the adaptation.