dear lord i resorted to cheating in the editor to solve that fourth one... blantantly unfair is right lol!

also: protip: make sure a corner of the stand is touching the thing that's different otherwise it might not press the button!

Anyway here's the answers for those that come after me, but i recommend you give it a try before!:
first puzzle: duck in the truck
second puzzle electrical outlet to the right of the fireplace doesn't exist in the Example room
bonus puzzle: a book on the shelf is redder color. It unlocks a room with a message that I don't entirely understand...
third puzzle: one of the knives on the wall above the sink is a shorter than its counterpart
fourth puzzle: I'm not even sure how to describe this one... in the first room you enter with the monkey on the chair at the desk... it is on the floor near it... look carefully at the floor, some of the floor is slightly blurrier looking... a little bit to the left of the wall vent... here's a picture of it https://cdn.discordapp.com/attachments/475090613021442048/806633869678870538/unknown.png

Even though I could only solve bonus puzzle and #3 legitimately, I still had a lot of fun!