Cryptic and evocative! Gorgeously designed, clever, quietly threatening. I really enjoy how much blank space is left for the imagination to fill in. The best kind of puzzle, where the result at the end is even more of an enigma. Really a condensed wonder, and in no small part due to its restrained and fragmentary character. So the fact that there is "not much to it" is actually a major aspect that really contributes to the effect!
It reminded somehow of the film The Invention of Morel which also had this strange artefacts and oddball quietude in a beautiful island setting. Something special here!
Your "method" makes a lot of sense. I often think about how the old school cartoonists would work directly in storyboards or in the strip without any preconceived script. It allows you to really work in the medium and allow it to surprise you (and as a consequence, US!)