WARNING: Contains very minor spoilers. And chimichangas.
There's a reason LEGO Marvel Super Heroes is one of the highest-selling LEGO video games of all time; actually, three reasons.
First, the characters. The game features not only the existing Avengers, X-Men and Ultimate Spider-Man LEGOs on the market, but a legion of characters and vehicles either only recently released in 2014 or not even created yet. From the Fantastic Four to the Sinister Six, this game includes the majority of Marvel's well-known characters along with a handful of lesser-known ones. Plus they've included the legendary Stan Lee himself as a playable character possessing multiple superpowers. What more do you need from this game?
Speaking of characters, the next reason is what the minifigures take part in: the story. You can tell the writers and game designers had fun trying to combine a coherent Marvel storyline with the quirky humor found in every other LEGO game. And you know what? They did it. The story features the Avengers, Fantastic Four and X-Men teaming up against villains like Magneto, Doc Ock, Doctor Doom, Loki, Abomination and Sandman, in an epic quest filled with crazy left turns that only a LEGO video game could have. And it all leads up to a stunning twist you'll never expect (so I won't ruin it for those who haven't played yet).
Finally, the gameplay. I was very pleasantly surprised just from playing a free PC demo of the game which was released online early last year, featuring the game's very first level, Sand Central Station. This level features Iron Man (Mark 6), the Hulk and Spider-Man taking on Abomination and Sandman in New York's Grand Central Station. But what blew me away the most during the level was the sheer number of abilities each character had, from Hulk's famous Puny God move from The Avengers, to Spider-Man's ability to actually swing around on a web. When I finally bought the actual game, I was thrilled to discover that the rest of the characters in the game were just as incredible.
So, if you're skeptical about buying this game, I suggest you try out the demo featured on marvelsuperheroes.lego.com first, and if you still don't feel like buying the game, then at least you technically tried it for free. But based on my personal experience, I think all of your doubts will go away and you'll want to buy LEGO Marvel Super Heroes right away.