I've been informed that Berts dagbok, the novel "Bert's Diary" was based on, was actually written back in the late '80s, though it's only received a film adaptation now, no doubt due to the success of the similarly themed "Diary of a Wimpy Kid". I know nothing of that American franchise, so cannot compare them.
I seem to be the first person to review "Bert's Diary" on IMDB. I guess nobody outside of Sweden saw it. It's not as bad as that might have you expect, but I'm not too surprised it didn't cross the pond, or even the Baltic Sea.
"Bert's Diary" is enlivened mostly by the performance of its two leads, Hugo Krajcik as Bert and Julia Pirzadeh as Amira. It's a fairly typical story about a boy who falls in love with the cool girl at his school, and tries to get close to her by stealing her diary, and writing one of his own for comparison.
The story really doesn't come together, and the movie feels episodic where it shouldn't. Being that the movie is Scandinavian, for the rest of the world probably the only surprising thing about the movie will be its frankness about nudity, ie. Showing Bert's bare butt as he gets off the toilet and is walked in on by Leila, causing him to later record in his diary "Hello diary! Leila saw my penis today." He is also shown in his underwear a few times, and even that seems a little "cringe", especially to the English-speaking world.