Regarding my recent WR in 100%. Turns out there are even more hidden items than I thought as I just found an additional hidden money bag in 3-1 right before the end of the stage. I deleted my run on the board and will continue searching until I am satisfied that we have found all items. I will also attempt to make some sort of coherent guide that shows the locations of the hidden items and how to reveal them.

Okay, so I have conducted a search of every area I could reach in the game. I actually found some interesting places you could reach where you wouldn't think to go, but for the most part I discovered that SOME stages have 2 hidden items. To be more precise, Stage 1-2 has two items and Stage 3-1 has two items, with all other stages seeming to only have one.

I will do some runs and try to get another 100% run in so others can watch it and maybe do some more searching if they think it is needed. Will confer with the mods and post my guide when it is finished. So far I just need to enter the exact locations and methods for revealing the items then I am done with it (for now?).

As far as 100% is concerned, you must collect all coins and power-up items as well as all the hidden items. Please refer to the appropriate guide to learn the location of the hidden items through all the stages (coming very soon).