Wonderful mod that gave me a lot of fun (and has a lot of cheese, which to me is a plus), although, having played for quite some time (enough to make a complete tierlist of items with comments as to when they are/aren't useful), I do have some feedback about some of the items, and suggestions as to how to improve them.

It seems you already buffed Jet Lag's IFrames and fixed Lunar Charm not giving you an item before the True Brain, which is good, however...

I believe the Overclocker should make a bigger impact. 400% is great, but it lasts such a short time. 6 seconds may sound like a lot, but - especially if you have multiple - it could be charged longer for more attack speed that lasts longer.

Lunar Charm could perhaps work so that having multiple of it give more items instead.
I know it may sound crazy, but it is a red rarity item, items that can have the largest impact on a run, and having multiple only slightly increasing the chance for a higher rarity item that may not even end up being good is a little... underwhelming, to not say lame.

Hearty Honeycomb should perhaps get a slight buff, to make it give 1 HP/sec + 1 for each 5% life missing ? (that would basically make it work like itself currently plus a living crystal) It simply seems very slightly weak.

As for Haemokinetic Grasp... it's currently kind of garbage and the only reason I pick it up in the first place is to trade at the Lunar Sanctuary- *ahem* as I was saying this item is really underwhelming (that's the word) and weak especially for a red rarity one.

Wayfarer's Waistcloak should get a buff to not be worse than Unencumbering Stone 99% of the time, likely by reducing the time needed to activate it or make it have a different trigger. (/ if the player had the buff then gets interrupted, the time needed to trigger it drops, as flat ground is so scarce, unless they turn back, in which case they likely aren't trying to move in a single direction and so the time should be the same)
To re-word, the time to activate the 20% speed boost is currently 1.5 seconds. The solution I propose is to make it so that if the player did run in a single direction for 1.5 seconds, they get a special effect which lasts one second after they stopped doing so. While this "effect" is active, the time taken to activate the effect is reduced to 1 second or perhaps even lower. If the player turns back, the "effect" disappears. (the tooltip could just mention that the cooldown is lower unless they get "severely interrupted")
This may be a little too much. Perhaps simply reducing the time for it to activate to 1.2 seconds would be enough.

Ball and Chain and Bouncy Ball both get the exact same comment from me: their 15% should become 20% and/or they should be moved to blue rarity.

I believe Barbed Lasso should have extra copies also slightly increase range, as having multiple is currently very rarely useful.

Unrelated: could you please bring precision as to what you exactly mean by "increasing by a diminishing amount" ?
For example, what would having, say, 200 DR do, exactly...?
Or by how much do all extra Automatic Defibrillator shorten the cooldown of the effect ?
I always assumed that, for items such as Times Have Been Tougher or Disposable Turret, all extra copies were half as effective as the previous one, but is this accurate ?

Apologies for the long read... I had a lot to say.

This was originally a comment, but they have a 1000 character limit, and this is over 3000.