You can actually break two lamps at the Plaza, and in the Greenhouse there are two plants you can use the lamp on, just for fun. But that's just me nitpicking.
In the third screen it's possible to derail the mining cart the wrong way, as has been mentioned in other threads.
I'm pretty sure everybody clicked on the well-known robot from Samorost 2, on the stairs next to the vacuum cleaner.
Nice touch, Amanita!
Can't think of anything else. Your list is pretty exhaustive.
PS: You can only click on the Samorost robot after you've defused the bomb.