Earlier this week Metal Gear Solid Snake Eater 3D released on the Japanese eShop, along with a theme based on the same game that gives your 3DS a Metal Gear twists. It also lets you play the Snake Eater song in the menus.
December 18th, the European eShop received the theme as well, for a price of €1.49 / £1.39.
In the US, the game released on the eShop as well, for $29.99. The theme is available in this region as well for $1.99.
Source: Pure Nintendo, Always Nintendo, Explosion