Can't say much else that hasn't already been said. Game's nearly perfect so far. LOVE how fast it moves and the pacing is non-stop. With that said, I went into the whole tool rental thing without over analyzing it leading up to its release and now that I've seen how it works, I'm a bit mixed on the whole system. Just a quick question about it, actually.
Does the game auto-save when you die? The risk/reward of renting everything at once and having the chance of losing it all is kind of irrelevant when you can just hit the Home button and quit the game before you die (kind of the same reasons why I disliked the pay-to-revive system in SMT IV). Unless you honestly accept a death as it's intended by the developers (lol) there's really no risk in just renting everything from the start (if you've got the Rupees).
Dungeon design, so far, while simple and short, is tight, satisfying and cohesive. Only two dungeons in so far, but they've goth scratched those itches well enough.