Despite being a Finnish production, almost all the dialogue in "Sisu" is in English, with only a few subtitled lines towards the end in Finnish. This might have been done for the sake of selling the film to English-speaking markets, but honestly, spoken language barely matters at all in this movie. In the whole 91-minute production, I'd estimate there's maybe 10 minutes of dialogue — most of it either exposition or profanity from the Nazis, and almost none from the Aatami, a man of so few words he makes John Wick sound like a Quentin Tarantino character.
Instead of using words, Jalmari Helander tells this story through powerful visuals. Each of the film's seven chapters quickly establishes a clear goal (e.g. dig for gold, cross a minefield, "kill 'em all," etc.) and makes the most of that straightforward clarity of purpose to build action sequences that deliver an ideal mix of suspense, splatter, and satisfaction. You could watch it without sound and it would still be perfectly comprehensible and entertaining. If "Genndy Tartakovsky's Primal" had a World War II-themed spinoff, it would probably play out something like this.
Every action movie has to find the right balance of badassery and vulnerability for its hero. In the case of Aatami, the audience knows he's going to emerge victorious at the end of the day the second we learn his battlefield nickname of "The Immortal," but his close calls with death are painful enough that we're always left on edge about how he'll make it through. I must also warn viewers that one of Aatami's animal companions suffers a particularly graphic death relatively early in the film, which is probably the hardest part of this otherwise entertainingly-violent movie to watch — though thankfully it's not his dog, who remains a welcome presence throughout the adventure.
Whether or not this elderly Nazi-killing machine is an objectively plausible character, he's certainly one we're willing to suspend our disbelief for. There's a borderline-mythic quality to the protagonist that fits with the movie's title, a Finnish word that we're repeatedly told in the film has no direct translation in English but roughly means "a white-knuckled form of courage and unimaginable determination in the face of overwhelming odds."
