Playing on a windows PC. Not sure what the ultimate cause was of this but - my first time playing the game, I got stuck in the second scene because I couldn't find the last two tiny people. I swear I spent way too long looking all over the place for them. It was really frustrating and eventually I gave up and went to a let's play to figure out what sort of weird puzzle I must be missing to uncover where they were hidden.
Turns out the big rat was supposed to be in the doorway and he'd drop the tiny people. I did think it was weird that I could no longer walk through the arch (invisible wall), and I had noticed that one of the dining chairs was partially tipped over, but I had chalked it up to weird supernatural stuff, not bugs.
So I restarted and tried again. Same issue.
So I uninstalled, re-downloaded, re-installed, and tried again. Same issue. (Hence the above screenshot)
Then on a hunch I started again but this time I turned graphics quality to the absolute lowest, resolution to the absolute lowest, and fur shading to "simple."
Big rat appeared bearing the tiny people, and I was able to play the rest of the game!
I'm not sure which of the three things did the trick (or if all of them together did), and it's not like I expect devs to fix this weird issue that's likely due to the age/inferior capabilities of my computer, but I wanted to post the issue and workaround somewhere on the off chance someone else runs into this in the future and doesn't know what to do.
Other things I noticed that were different when the game worked like it was supposed to: In the bugged playthough, the robots wouldn't make robot noises or move on their own when put down. Picking up the orb shaped robot up and putting it back down triggered a loud banging noise which would not let up unless I picked it back up again, and then it would continue when set back down. I thought it was the giant rat trying to pound the door down until I realized it was tied to me picking up the robot. Not sure how any of this is related to graphics quality/resolution, but somehow that fixed it all.