10 Video Game Easter Eggs That Change Everything

1. 1999 Mode Literally Changes The Game - Bioshock Infinite

And finally, we have an Easter egg that literally changes the game in Bioshock Infinite.

By entering the iconic Konami code (up, up, down, down, left, right, left, right, cancel, confirm) - or actually just beating the game once - players can unlock "1999 Mode," a special hardcore version of the game which, in the words of director Kevin Levine, "[doesn't] feel like BioShock."

When pressed further, Levine added, "[non-hardcore players will] hate this mode. That's okay - it's not for them."

To be more specific, 1999 Mode - referring to the 1999 release of the developer's System Shock 2 - basically reduces everything helpful in the game world to make the experience that much more punishing.

There's less ammo, health, and respawns, while enemies deal more damage, respawns cost money (and running out of cash will send you back to the main menu), and both auto-aim and the ability to change difficulty have been removed entirely. Oof.

As the game itself warns, the mode is only for "the best of the best" due to its near-total lack of accessibility features.

Originally it was intended to more explicitly emulate old-school shooters, but ultimately the decision was made to focus on it being a hardcore rendition of the regular game instead.