It's excellent, but missing something.
I think it would me much better with the right color, lighting and ambient audio, but perhaps that's just me. I'd be honored to help you out in that department if you're interested. I loved the characters and this is a solid concept. It doesn't just "try to be weird", it also charms you by letting you roam freely and take in the weirdness. It had a bit of a "pixel hunt" element to it because of its monochrome, but the mechanics and design are ingenious. I wonder what inspired you to do this? You explain Submachine in depth and it would be even more interesting to see how you came up with it.