As we all know in CY+11 games have been ruined in every aspect imaginable which includes the progression system of the game.
How would you do one?
>what's the genre?
>how do you "power up"?
>what do you gain from it?
>when will it end?
Mine would be a relic system in a Indiana John's type of game but with more emphasis on combat.
After you complete a dungeon you'll get rewarded with a relic that has a blessing but also has a curse.
For example:
>you can dodge more effectively
<but you'll never be able to parry
In the beginning you will only be able to equip one relic but after a certain point you'll be able to equip two and by the end three.