New game+ is almost exactly like the regular story mode, but you get to keep all your stuff. Not unexpected, of course, but it does somewhat undermine the structure of the game. Now that I've bought all the weapon upgrades and miscellaneous items, I don't really have anything to strive for (aside from some perfunctory xp grinding to get up to level 10).
That said, Bastion still has a trick up its sleeve - the idols. The idols are a nifty idea, and probably the most innovative part of the game. If, like me, you are in danger of becoming jaded by the easy difficulty of the default game, you can go into the Shrine and activate one or more of the ten divine idols. Each one has a different effect on gameplay, from making enemies reflect attacks to removing random potion drops.
I like this a lot more than just a flat difficulty slider. Adjusting to new idols requires me to rethink my tactics and habits in a way that just straight up beefier enemies would not, and if I find a particular aspect of the game too tricky, I can just deactivate that one idol without completely going back to easy mode. Plus, the idols give you more xp and gems to compensate, and even though I don't need them, it's a nice bonus. I think this should probably be standard for how games do adjustable difficulty.
Bastion may be a simple game, but it is continually surprising me with its ability to get the basic action-rpg formula right.