A copy comedy starring Jonah Hill and Channing Tatum, written by Chris Miller and Phil Lord, and with side roles played by Ice Cube, Dave Franco, and Brie Larson. Actually, maybe I shouldn't be that surprised that I really quite enjoyed 21 Jump Street. It's just that, based on the trailer, I really expected to dislike it.
Luckily the machismo humour and dick jokes took the backseat for most of the movie to a more nuanced story about high school stereotypes, modern teenage culture, and the idiocies of action films. Don't get me wrong, they're still present, but it wasn't just 2½ hours of them in a row, and even when they were present they felt satirical in context. I think this is actually a rare American comedy that is both fully self-aware and intelligent enough not to ram that realisation down the audience's throat.
There are still moments of excess: excessive swearing, excessive violence, excessive sexualisation. I think the idea is to point out how ludicrous these elements of the 80s and 70s films the movie is satirising were, but they're a bit heavy-handed so just come across as pandering. The main characters are also both idiots and the entire premise for the plot is ridiculous, but that at least is a direct satire and so forgivable.
Overall, I enjoyed myself, the movie made me laugh, and a couple of moments actually showed it had some emotional and cognitive intelligence. In other words, it greatly exceeded expectations, even if it isn't an instant classic.