- Superhot actually took the stop time mechanic from Time4Cat [1], a free flash game. With guns added, and a unique art style, players were drawn in. It also helped that the game was originally created for the 7DFPS challenge where it received initial interest.
- Minecraft gained popularity originally because it added enemies that came out at night, something the world building genre hadn't really seen before (and so the reviewers jumped on it). Voxel engines weren't new, but it was unprecedented to use them to give creative ability to the user like so ('user customization' being a common theme in many successful games, see: TF2 hats!)
- Same again with Portal, the mechanic was neat, but the story is what people always talk about.
- Monument Valley strikes me as another, great idea with the isomorphics, but also great art style and animation regardless. The progression of puzzle difficulty is what keeps the player interested though, as the learning curve is subtle enough to work in the casual games mobile market.
- Here is an example [2] of a good idea on the scale of Portal, but so far poor execution, resulting in lackluster gameplay. It is Pillow Castle's First Person Puzzler where picked up object's are re-scaled depending on your perspective.