Casual should be the triangular pyramid Rubix cube, and dark souls the pentagonal D12 one.
Cause the 2*2 cube is the same as the 3*3.
There's some parity issue where you can get down to two side pieces out of place after solving the corners on a 3*3, but otherwise they're the same puzzle
* It must be accompanied by a cute or cool figure (or both).
* The figure must be small, not a keychain but something that we could put over the screen.
* Artbooks are cool but they must be as an extra.
* Nobody (but scalpers) care about boxes.
The reason i have always heard that games where super difficult for was that they didn't have enough storage to make a long game so they made them super hard to make them longer.
Allegedly, one of the reasons for those old games being so hard, was that developers and publishers HATED rental stores. If someone could beat the game during a single $1.50 one-day rental, that's a fifty dollar sale the publisher would never get, or so the story goes.
Also, of note, the reason that the old NES/SNES games were so difficult and lacked saves is that they were often ports of arcade games. They were explicitly designed to kill you so that you had to put in more quarters - first example I can think of, Contra.
Take Super Ghouls and Ghosts for the SNES for example. Nice game, but very stingy with the lives, you died in 1~2 hits, there were no checkpoints, you got bounced around whenever you took a hit, and the game made you defeat it TWICE, side-by-side, in order to beat it. Thats just bad design!
@Andy, old NES/SNES games were frustrating af, often because of the poor controls, design choices, lack of save or checkpoints, or a combination of it all. Sometimes the gameplay elements aren't difficult, it was just the overall design that made it hard to play to completion.