Everything you need to know about Deadpool can be summed up in the mid-movie montage, in which the newly coined Deadpool tries to hunt down the man who turned him into Deadpool. You see the evolution of his costume, you see the evolution of his skills, and it's all set to a deliberately tacky 90's style movie rap explaining Deadpool and who he is. It's a closing credits rap, but it's right in the middle of the goddamned movie.
If you need to know more, know this. Deadpool is hilarious. Its as joke-dense as an Archer episode. It's funnier than nearly every mainstream comedy movie in the past five years while also managing to be a kinetic action movie and a solid superhero tale. It's filthy and violent and most importantly, it's just right. If you got a picture in your mind of what.a Deadpool movie should be, if the red band trailers got your hopes up about what a Deadpool m ovie could be, rest assured, Deadpool is that movie and more. They nailed it. They cared about nailing it, and they nailed it.
How much fun is Deadpool? I'll tell you how much fun it is. The Onion AV Club gave it a "B-", which is their official grade for anything they might lose street cred for by admitting something gave them joy. That's how good Deadpool is.
Non-spoiler highlights include every moment Negasonic Teenage Warhead is on screen, every single joke at the expense of other X-Men movies, the relationship montage that shows Wade Wilson and Vanessa, and the cab driver from the trailers, who has a bigger part than you'd think and a hell of a payoff. Also the opening credits, closing credits, and post-credits tease.
It's not for everyone, obviously. If you have those things, those, what are they called, sensibilities? Offendableole ones? Ones that don't appreciate dick jokes and severed heads, usually at the same time? Then skip it. But otherwise, go. It's the best.non-MCU superhero movie maybe ever.