Snake's Revenge was released in April of 1990 in the US, and on March of 1992 in Europe
Although the title implies itself as a sequel to Metal Gear, it really isn't. In fact, after learning from one of the game's developers that Snake's Revenge was being produced, Hideo Kojima was driven to create the true sequel Metal Gear 2: Solid Snake which was released for the MSX2 computer system on July of 1990.
As with many Konami games released internationally, the instruction manual radically altered the storyline which is inconsistent with the actual plot of the game, this included altering Big Boss's name to Higharolla Kockamamie (which was a parodical take on Ayatollah Khomeini).
March 1992 - Consoles + N.8 (Page 126-128)
May 1992 - Joypad N.8 (Page 70-73)