For now, I'm going to place down a basic idea and sleep on it before really going into any detail.

So, instead of having some wildly overpowered healing weapon, why not implement something that replaces your shield.

I'm not talking about any sort of mid-level cooldown (as that would be disgustingly, gamebreakingly OP). This (vitapod? I don't really know what it would actually be that you're holding as a shield) would give you a small boost of hearts at the beginning of the level below the one you used it in (letting you switch into a real shield).

I think that it should start at 3 or 4*, with the 3* giving three hearts per level, the 4* giving four and a half, and the 5* giving six. It could also be based on what level one is in, though hearts are pretty rounded units to be working with.

To sum things up, it would be an device replacing your shield, that would give the owner of that shield device a certain number of hearts at the end of the level they used the device in. This amount of hearts would be based upon either the star level, the clockwork level, or a mixture of the two/something completely different. The name, look, description...mostly everything about this device is up to discussion...as is the workings and base idea of the item. :D

Just in case I didn't make it clear enough, this would completely replace your shield, and prevent you from shielding at all.

Discuss. Especially you, Lugs.