Suggestions:

1. Make a secret number that is MYSTMAN12'S number (you could put the original secret yctp code but whatever you want). If you call him, he will run at you at high speeds and chase you screamin (make the screen's colors go like this when he's getting closer
2. When you are afk for 20 seconds or smt, every second untill you press any button makes mystman12 move faster and faster. When you press any button, go back to original speed (not necessary to do but l think it adds to the idea of not going afk XD)
3. Make the ladder(s) to the basement interactable.
4. Make a voiceline for Micah when he notices that the player drew something on the INTERACTABLE OBJECT/BOARD
5. Make a jumpscare (something like a screamer) if you access the BBCR video in the main menu (l am not going to spoil how do you find that).
6. Add JUST ONE more character (l'd love to see Micah's cousin in the game somehow).
7. You should add some room which has a window and you have to break it by making Micah falling there to collect some cool secret (it could be the number mentioned in the first suggestion!!)
8. Make a secret which changes Micah's clothes to NULL's ones.
9. Add a bear trap item (unless you think that the banana one is the same). To make it different than the banana peel, you could make the player also get trapped if he touches his own trap.
10. You could make one of the paintings in the game pickable (l would prefer NOT to make that item spinnable so you will not know that it is pickable) and you could make an empty canvas where you could place the painting and, thus, unlock another secret!!!!!!

l think that's it!!!! l love the game, great job to all of you. l hope you hear my words :D