Missing keys in games

[Serguei2]

It's funny to see how programmers forgot to put keys in games.

 

I wonder if there's a story behind it or it's just an accident.

 

 

Final Doom: Evilution

 

This is a secret level. You can decide to skip it.

 

 

Blood

 

Chapter 4, level 5: you can't complete the rest of this chapter.

 

Both games have patches/newest versions to correct them.