That floating platform is the one you are after the tutorial section, where you see the "bridge-gate" opening, you can't see the part with forest because it unloads after you enter the castle, will be fixed in the future.
Glitches are not really a thing you're supossed to interact to but they can give hints about secret places, the theme is that you are in a simulated corrupt world and this glitches are kinda of the proof that things aren't going well, but I have to work on a lot more things to merge that well in the game.
I know I have to work more on shortcuts when they appear, right now I can only use visual feedback for that to happen but sound cues could make this a lot easier. It's kinda hard because for example in the first Zelda you can see the full room all the time, so if a secret appears you will notice, but in a 3D space, large at times, it's kinda hard without forcing the camera.