Hidden? Not really. Waldo is the closest thing to the camera, and therefore quite prominent. Also...it could be a coatrack for all we know. Needs more contrast, and sharper focus.
Needs to be sharper focused and more light. That is not the back of Waldo on the right side is it? That's not hiding him. Other than that I haven't spotted Waldo. If I come back and find him I'll raise the score by 2 points, proving he's there. Like the sepia tone.
O.K. I see a back of a likely Waldo..... Is this sepia or B&W, sepia, I think. Why? Lots and lots of grain takes away from the crispness of this photo. I know you probably couldn't close the door....5 Swash
Unfortunately the person isn't hidden, so much as cropped heavily. Unfortunaltely the photo is a bit grainy, perhaps from low light, and isn't terribly interesting to look at.
I see Waldo there on the right, so you met the challenge alright. However, the photo is too grainy I feel. Did you do this on purpose to give it a kind of old photo look?