The first thing i noticed so far is that the Overlay feature is not working like supposed to at all, is this a bug or did you disabled it for the beta? I personally haven't found the coin flash noticeable enough to be bothersome, even on relatively coin-dense areas such as Headgrinder's area on "For Egomassive". What i did found pretty noticeable however is that, on certain collectibles such as powerups and golden creatures, the game will draw it even when it no longer exists/has aldready been collected.
Edit: Also, Bank 15, Object 25 right now is being drawn fully opaque before the game assigns it a variable transparency, which can sometimes result in notcieable flashes. And i found out Bank 2, Object 13 is sometimes drawn as 2,12 for some reason.
Also, a copy of certain OCOs appears on the top left, not an image flash, An actual, INTERACTIVE copy of the OCO. This is particulary gameplay-wrecking on Golden Creature OCOs (See attachment: That little disk at the very top? it's supposed to appear in the pit left of juni.)
Edit: Another one. Bank 14, Object 20 (And it's spiky and golden counterparts) will sometimes be drawn despite the fact that they spawn hidden undergrond and only after they are loaded they make their "Popping Out" Animation.