Quite a solid effort for your first game! The environment is creepy, and just confusing enough to be challenging. I like the idea of an invisible monster. The echolocation is a cool way to work with that, since it gives you just barely enough information, while still being disorienting.
I wasn't really sure if I was supposed to be able to fight the monster - left-clicking seemed to trigger an attack? animation, but I don't think that did anything. Running worked fine, though.
(I'd also love to see a Linux build included in the future, Godot actually does all the work for you, you just have to set up an export.)