A Roguelike, where the hero will keep his memory after each death, but the world will be reverted back in time (Something like in the Re:Zero or Legend of Zelda: Majora’s mask). So
- Theme - you have to collect 7 crystals of power (each opens some game mechanics).
- Progression - if the player stands in place and do nothing (almost) his mind is restoring.
- Fall - The game is build of falling of the player: he cannot win without deep known of the story.
- Randomness - You could create side quests randomly for each world cycle.
Hope it helps.