#3: Zork 1 [Unlockable In: Call of Duty: Black Ops 1]
This is the most mismatched pair of unlockables ever — in Call of Duty: Black Ops 1, you can exit your chair in the opening main menu and access an Easter egg computer. From there, it’s possible to load up a copy of the text-adventure game Zork 1 and play the entire thing from your console.
Zork 1 is a strange little surrealist text-only game, where you’ll have to type in commands. It’s probably the most basic game on this list, one that was absolutely available on extremely primitive computer — even if the timeline probably isn’t exactly right in the logic of the game. Whatever, you can enter the darkness and get eaten by a Gru. That’s what matters here.
#4: Sonic The Hedgehog [Unlockable In: Sonic Generations]
In a game that totally celebrates the past, it’s only logical that you can unlock a full playable version of the original Sonic The Hedgehog in Sonic Generations. The PS3 / Xbox 360 era Sonic game stars ‘modern’ Sonic and ‘classic’ Sonic, complete with old-school sidescrolling levels.
To access the original game in the franchise, you’ll need to purchase a Sega Genesis controller from the in-game shop. Yes, really! With this tool in hand, you’ll be able to play the classic, sprite-based, blast processed game in silky fast superspeed. Gotta go fast, indeed.
Check out more fully playable, complete games within games on the next page.