This was short, but so atmospheric! I definitely think I'll have weird dreams now... I played through each ending in the order 2,3,1 and enjoyed all of them (I only wish it was a little longer to find out some more!)
Two potential issues I noticed, the piano needs a self switch else I can continually switch it on for no reason, and I did notice a bad loop of music in the riddle room (possibly because I spent the longest in there...)
That riddle was tough... I spent a long time trying to come up with answers, but in the end, I cheated ^^' I really don't think I would have been able to get that on my own, to be honest, the answer didn't make sense to me. Well, I understand it, but I wouldn't have clicked that together. You might want to have the solution somewhere so that the ending is accessible to all.
Overall, you did a great job! <3