The difference is that RPG leveling systems don't care about you passing a specific challenge - they just care that you've spent a certain amount of time in an

The difference is that RPG leveling systems don't care about you passing a specific challenge - they just care that you've spent a certain amount of time in an area. In Metroid and Zelda, if you know the solutions to the puzzles, or are just really good, you can blaze through them and get to the good part in a fraction of the time spent before. That's why there's an entire subculture of people who speed-run Metroid-style games, and not so much for Final Fantasy. I think that that kind of progression is a more accurate indicator of a) whether the player is ready to handle the complexity that the new ability brings, and b) the value the player has received from the game, so far (if we're dismissing the notion that time spent is necessarily proportional to value).