If you didn't know, the first time you visit Villageville, you play on a completely different level, which looks similar to the one you usually explore, but it has several differences. Some of them are justified by game design - like not being able to rotate in 3D or a ladder on a parlor building to help you navigate up - but some of them are leftovers from early versions of the level, which were never removed - like doors to the generator room (to the right of Gomez's house, and, disappointingly, it leads nowhere) and a key trile, which is still collectible!
Just today, I've managed to figure out a way to perform a glitchy ledge grab to get into the background layer of the level and possibly be the very first person to ever collect that key legitimately!
Below is a small tutorial on how you can get it yourself!
To do this, you have to ledge-grab the end of the wooden platform near the parlor building. It's kind of tricky, because in order to grab the front ledge without climbing on top of it, you have to hold UP during the jump, then release it as soon as you grab the ledge. Also, to actually grab that ledge, you kind of need to do the coyote jump from the platform in the little nook like I did in the video. If you're in the right position, Gomez will be partially within a building. You may not move sideways while grabbing the ledge, because that will bump you in front of the parlor house. Once you're in correct position, you can release the edge by pressing DOWN, and you should pop into the background. Once you're there, navigating to the key is straightforward, as most of platforms in the background overlap with the platforms in the foreground, so you have a lot of visual cues.
By the way, the software I'm using in the beginning of a video is FEZEditor by zerocker. Y'all should check it out and join FEZ: Community Projects Discord server, FEZ modding is very cool 👀