1) push the yellow block out and use it as a platform to jump to an opening in a wall. There are lazers back there and some non-void screws that help you get up to a ledge from the first red screw in this room.
2) At 2nd red screw, above and to the lef (instead of the right where you go up normally) there is a ledge you can grab onto. Above that ledge you can get up to a shelf
3) I'm like 90% sure this was exp, but: At the top area, there are 2 cylinders. Ground pounding one of them gives you a platform to get to one area, ground pounding the other lets you get to another area.

If it's not one of those, I don't really remember sorry. I didn't think to write it down at the time since I didn't even know what they really were. I'll try to remember some more though if those aren't it

Are you witholding info to be the first one to discover the secret ;) idk if I remember all of them but I'll try:
- Anxiety Tower: End of level
- Hollow: Top of Church
- Hollow: Take the bat off the top of the drill
- Hollow: Inside tree, there's a stump at the top with one on it (can either cheese a jump from boss door or activate path up to it from using red screw in unflipped mode)
- Hollow: Fish puzzle I mentioned earlier
- Park: Out of bounds from jumping over fence off pole, dig to the left, turn left, burrow under mini tunnel to secret hall
- Park: Inside top hat guy after burrowing under
- Park: Move bookcase to corner with off-center ceiling piece, jump attack upwards
- Park?: This is the one I don't remember so well, not even 100% sure it's in this world. But I think it might have been inside the treehouse thing, with the moving panels and patches of dirt to dig in. Some places I think it could have been:

Hey yeah, we can help. Just a quick question, where did you find your CURRENT screws? By my estimations, if you find the secret area and the anxiety tower screw, you'll have all of them.

Mind helping us out here? lol

It sounds like you guys know of a place to actually use the screws? I have 9 of them now but idk where to use them. Can you lmk where to use them and the location of the 2nd screw in anxiety tower?

It sounds like you guys are missing one in Wollow's Hollow. I was really proud I found this one LOL. So in the room where the coffin with 3 zombies is (accessible via the level door at the top of the shop) there is a wall with 3 fish symbols on it. This is related to another void screw.

If you want a direct explanation of that, you're supposed to kill the 3 evil fishes in the level. There's one in the graveyard pond and I think 2 in the interior tree pond. I killed them with bomb birds. I was only able to figure this out because for every fish you kill, one of the symbols is lit up, and I happened to have killed one and noticed they stay dead permanently. Anyways, go back to the symbols and they'll reveal a void screw

How did I miss such an obvious one? Thanks. And yeah I had that same theory too, I explored it a while ago and couldn't find anything. When you get too low you instantly get sent to a checkpoint even if you only fall for a little bit. Only other place I could think of is the regular tower seeing as that has no screws aside from the hub area, perhaps there's a window that doesn't have an obvious "break me" indicator like the one you have to break near the rocket ship near the top. There's a lot of windows though and I don't have much faith in that theory anyway.

OH RIGHT. I completely forgot to mention theres ONE inside the actual zone area. Look in the left corner when you enter through the door. It should be fairly obvious where it is ;=)

As for the actual proper last screw I'm missing; MAYBE anxiety tower? It's the only place where there's 2 screws so far. Issue is : I legitimately don't know where it could be. I theorized it might be in those chiseled out sections that require you to drop down, but it's just empty space. There's no actual content there, maybe the despawn zone isn't that low.
I ran the tower like 3 times already scooting by and still haven't really spotted anything out of place.

Actually, if you say there's two doors after that, and you only have one left, then that means I'm missing another one that you already have. Could you tell me which other one I'm missing?

Damn, here I thought I was one away from being done. Anyway, for the one you're missing, on the roof with those two guys asking if there's a bar or a bat, ride the bat to the spinny tower like usual, but then immediately ride back on after he drops you. There will be another stationary bat waiting nearby, jump off and grab him and he'll take you to the screw.

Thanks for the tip, and good luck on finding that last one.

No, there is like 2 more doors after that lol. I'm definitely sure I didnt get the bat one though? Can you explain where it is? also I can tell you that you're missing one in the church. Look UP. It's after the hard platforming section near the ledge. When you reach that section with the door, go back to the ledge, and look backwards. You'll notice 2 short pillars. Jump backwards and headbutt into the pillars, then jump onto the other side and you'll find one screw.

Now if only we can find that last screw, eh?

I've found 7 so far so assuming there isn't more doors beyond that one that needs 2 screws I'm guessing I need one left. Here's all the ones I found.

2 in the anxiety tower
3 in the park
(inside the building with the tophat at the start, inside a ceiling tile after you push the shelf, out of bounds through a hole you dig through on the east side of the map)
2 in the hollow
(inside the tree during regular world, high above the entire map after grabbing onto a specific bat)

I'm guessing the last one is somewhere in the hollow to match the 3 in the park but I'm completely out of ideas, if I had to guess it's behind the locked door close to the music box but I have no clue how to open it or if it can be opened at all. Would be handy if you found the one I was missing already lol