Most Unusual Item: Patra Rod
Item I'm Most Likely to Use: Essence Chain, or Heart of Ice.
Here are my thoughts on each item:
Aim Bow: This is a stunning effect, and a very cool concept. The problem I find with it, is that it is hard to aim. if you were going for a distance effect, like pulling a bowstring, you succeeded, but it makes it a bit clumsy to use at angles. Making the pointer 'float' instead of having it move back while the player presses a button might be a wise improvement. You could set it up as a script option.
Essence Chain: In terms of gameplay mechanics, this is absolutely divine. I would have liked to see it draw HP from enemies, and magic from Wizrobes, or things of that sort. My only complaint is that some of your loops seem to cause lag, but that was likely due to running the debugging
console while testing it.
Gravity Rod: It was rather difficult to gauge what I thought of this. The quest file didn't actually give any special ice/fire triggers, or puzzles on which to use it. As a weapon, particularly in that bullet hell, it did nothing for me. I resorted to using the Patra Rod to kill everything, as I couldn't survive long enough to use the Gravity Rod.
It would make a nice puzzle mechanic, if so employed.
Heart of Ice: This is a nice little compact ice beam, both for overhead, and sideview. The test file shows some of the problems with using that sort of thing with ZC, as the ice vanishes when you leave the screen, so getting up even one screen was pretty much impossible. It's certainly fun, and useful for quests, and I may eventually use it meself.
Magic Clock: Sometimes, simplicity is beautiful. This is a perfect general-use item for puzzle-oriented quests. I do however see how it could be abused in boss fights.
Patra Rod: What can I say? I love the Cane of Byrna. The flaw here, is that it doesn't persist when changing screens. Otherwise, Ace.