Is a game pack and a memory card the same thing for Nintendo 64?
Not quite. A game pack could refer to either the Cartridge placed into the Nintendo 64 directly and is used to store the game's data, or the attachment that is placed on the back of the N64 controller. A memory card is the unit that saves the altered data for the game. There are two types of memory cards for the Nintendo 64 games, the built-in memory storage that is included in many of the N64 game Cartridges, and the memory pack, this is an attachment for the controller itself, and is used for any games that require a save feature for your profile, but do not have one installed in the Cartridge (an example game would be Gex 64, it requires that you save, but cannot save the game in the cartridge).