Just in case you've never heard of the "Merc with a Mouth" before, here's a quick primer: Deadpool is a former mercenary turned villain turned quasi-good guy anti-hero from the Marvel Universe. Through a secret weapons program that also produced another popular Marvel superhero, Wolverine, Deadpool gained a rapid healing ability but at the cost of much of his sanity. He's well known for constantly breaking the fourth wall and having random conversations with the voices in his head through various colored text boxes, which is something that carries over from the comics to his game with some mixed results.
Deadpool's story - or meta-story, technically - starts off with Deadpool "convincing" the game's developer, High Moon Studios, to make the very Deadpool game that you're playing. A couple of remotely detonated explosives and a crayon-revised script later, you'll find yourself hacking your way through hapless guards and X-Men clones while arguing with one of High Moon's executives over the game's budget, before embarking upon an adventure to save the world from some D-List Marvel villains. The game definitely doesn't take itself too seriously, with Deadpool constantly arguing with himself and delivering sarcastic quips while running through level segments that take place within 8-bit worlds or a colorful hallucination.
Much of the game's humor is crude, juvenile and even a little sexist at times, but amid some of the tackier jokes, there are several genuinely hilarious moments (a few of scenes between Deadpool and his former partner in do-gooding, Cable, are particularly clever.) However, some of the reference-heavy jokes might be lost on those who only have a partial knowledge of Deadpool or Marvel comics in general. Deadpool does try to help out players who aren't well-versed in the Marvel setting by having quick Behind the Music-style cutscenes that explain who some of the characters you meet are all about.
When it comes to combat, Deadpool's mix of sword-play and "gunkata," is a definite highlight that has much more depth to it than at first glance. While some of the enemies you face initially will make it feel like you can you'll just be able to button mash your way to victory, they'll start throwing grenades, blocking your attacks and using ally-boosting abilities that can make them very tough to handle. You'll have to vary up your attacks with counters, ranged attacks and combos in order to do the most damage without getting damaged yourself, and some enemies are just nigh-impossible to take out unless you devise a good strategy to weaken them first - usually with a bear trap or two.