The Cameo: Many characters appear in the endings and on the stages. Thor, She-Hulk, Scarlet Witch, Nova, Drax the Destroyer and Iron Fist appear on Thanos' stage as statues and are broken free in the heroes' endings. Mephisto and Lady Death can also be seen, naturally not turned to statue. Also Adam Warlock in Juggernaut's ending and Cyclops in Wolverine's ending (as well as the other X-Men who were not brought over from Children of the Atom, plus Jean Grey, in Psylocke's ending). For Thor, She-Hulk, Nova and Iron Fist it also counts as an Early BirdCameo of sorts.
Clothing Damage: Happens to Captain America when hit with an Infinity Move.
Combat Tentacles: The only plausible explanation as to how Shuma-Gorath made the cut over Doctor Strange.
Cool Boat: Doctor Doom's stage is a submarine slowly rising up to the surface.
The Final Boss with Thanos, as he has the Infinity Gauntlet and the six Infinity Gems. To put this in perspective, in the story this game is based on, when he had that he was pulling punches and still killed every enemy that directly fought him (which is was a larger cast than what appears in this game)
Elephants' Graveyard: Shuma-Gorath's pre-historic stage features several massive skulls and bones, one of which appearing to be a Triceratops.
Glass Cannon: Blackheart is surprisingly fast and strong for a demon of his size, but he's actually pretty weak defensively. Spider-Man's health is also very low but he's more than fast and powerful enough to get the job done.
Genius Bruiser: The Hulk, where he's in the guise of the Merged Hulk/Professor persona. (remember, The Green Scar from Planet Hulk and World War Hulk had yet to be created at the time) There is also Spider-Man and Iron Man, as well.
Multiple Endings: Thanos in the console ports has an ending where the player can choose to seize even more power with the Infinity Gauntlet, or renounce it and become a simple farmer on a distant planet (Which actually happened in the comics too.)
Most of Thanos' elements, such as winquotes and the like, are outright taken from famous comic panels such as one of his super move images being taken from the iconic cover of Issue #1 of the Infinity Gauntlet storyline. His "I want more power!" ending image is taken straight from the comic issue where Thanos becomes the new Eternity. Even his "renounce the power" ending happened in the comics storyline. After all was said and done, Adam Warlock ventured to a distant planet and indeed found Thanos there having turned his old costume into a scarecrow and become a simple farmer. Said 2nd ending in game has farmer Thanos and features his scarecrow in the background as well.
Thanos' stage is the same shrine he built for Lady Death in said storyline, albeit with two Thanos stone heads instead of one skeeltal face and one based off of Lady Death.
Juggernaut's ending at one point shows an image of a triumphant Adam Warlock wearing the Infinity Gauntlet, said image being directly inspired by the front cover of issue #1 of Warlock and the Infinity Watch.
The Worf Barrage: In a sense. In the final battle, Thanos has all six of the Infinity Gems at his disposal. Against other enemies, all you need to do to make someone drop whichever one they have equipped is to hit them with a special move. Not Thanos, no. For him, you'll need to use a Hyper Combo.
Updated Re-release: Received one with the original Marvel Vs. Capcom in Marvel Vs. Capcom Origins. It includes HD graphics, a store to unlock features (illustrations, cheats, etc.) and online play and is also the first time that Anita is available overseas since she's unlockable via the store too.