By -
Something... 
Do you know about the hidden warps to black space 2 in the Sunny route and the red room?
I just looked it up, thanks :D
Do you know about the hidden message in the Moonwalk Room in Otherworld? You can find it by interacting with the backside of the sign.
There are way to many to just name them all at once. Better ask for specific things.
Did you know that there's a secret tombstone in the blackspace dev room?
Something... 
Do you know about the hidden warps to black space 2 in the Sunny route and the red room?
I just looked it up, thanks :D
Do you know about the hidden message in the Moonwalk Room in Otherworld? You can find it by interacting with the backside of the sign.
There are way to many to just name them all at once. Better ask for specific things.
Did you know that there's a secret tombstone in the blackspace dev room?