I wasn’t actually referring to game mechanics in the post that started this particular discussion, but to the fact that everything new is based on something that already exists. Almost any new game is a slight variation of something existing, and it’s only over time the differences get big. The only difference between Wolf3D and Commando is the viewpoint 
What?
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I wasn’t referring to you not referring to gameplay mechanics, I was replying to the part of your post talking about how you can’t explain everything about a certain topic easily.