Bastion

Bastion is an indie game on steam.  It's an action RPG.  The plot: a calamity struck, destroying much of the world around you.  You go to the Bastion, a safe haven, and collect artifacts from the world in an attempt to reconstruct it.  The game was superb.

Structurally, the game is a lot like Legend of Mana (an action adventure RPG where you rebuild the world by searching for mana artifacts).  It differs with its focus on narration.  Legend of Mana was a quiet game, whereas Bastion has a narrator speaking for pretty much the whole time.  The things that he says depend on your actions (eg, if you defeat all of the monsters in an area, he says something different from if you only defeat some of them).  The focus of the game is the narration and figuring out what happened to the world by advancing the story. 

The game is difficult enough to be challenging but easy enough not to get in the way of the story.  Also, each of the different weapons that you can use are different enough from one another that combat stays interesting.  By the end, my favorite was the pike (it has an amazing reach and pierces armor) and the rocket launcher (it's a rocket launcher in a fantasy setting). 

There are gods that you can worship to make combat more difficult and an area that you can go to test your combat skills with 20 fights in a row.  The first time, these areas are hard enough on their own, but once you get the hang of your favorite weapon combo and get a few levels, it isn't hard to do even with all of the gods. 

Also, there is a leaderboard with how well people do in these areas, and it's sorted on which gods you complete the challenge with.  In other words, there are a bunch of people who have all completed it with the same difficulty.  It's unclear how it's sorted after that.  There were a few hundred people who had already finished with all of the gods by the time I completed it, but I still managed to get to #6 on the leaderboard.