What's One "Old Game" Mechanic That You Don't Miss?

[noob]

I kinda want to see an indie game where you have to unlock easier difficulties, just to be contrary.

Like how Lost Vikings 2 gave all of your characters superpowers if you managed to get a character killed in the first level (which has no enemies or stage hazards).

There is also a devil may cry where you unlock lower difficulties by losing a lot.