The ESRB has published their rating for Marvel’s Wolverine, and it brings up some interesting details.

Insomniac’s latest project has received an M17+ rating, with this summary:
Marvel’s Wolverine is rated M for Mature 17+ by the ESRB with Blood and Gore, Drug Reference, Intense Violence, Partial Nudity, and Strong Language. Also includes In-Game Purchases.
If you’ve seen the game’s trailers, you shouldn’t be surprised by its descriptions of the game’s gore and violence. But it also says this:
A handful of sequences briefly depict a character’s exposed buttocks.
And of course, some characters say fuck and shit. Regarding in-game purchases, we should probably expect the same kind of added content that Insomniac has added to the Marvel’s Spider-Man games.
These are probably the sort of details Insomniac expected would be controversial about the game, and not the knowledge that this could be one of Sony’s last game releases on disc. But that’s arguably more imperative than any debate if this game’s content is too adult or costs too much.
