With the low poly graphics, and the pixel filter this looks really stylish. The sounds (especially the blizzard outside) make the atmosphere work too. The art style over all is one of the top ones in the jam- it really sells the atmosphere.
As for the gameplay- all the types of gameplay were good, but I feel they could be polished a bit more. For example- it irked me, that the door to the house stayed open all the time. It's freezing outside after all! As for the platforming section- controls felt fine but I sorta don't know why it ended when it ended. Did I run out of time? Was that the end? The office nightmare was perfect- no notes here :) Generally I feel like you spread yourself too thin- this was just a 4 day jam, and I believe all the elements would be fleshed out more in a longer one.
As for the theme... I know that I should watch for the "guest", but I didn't see any sign of him! Could you give me a little hit what I should look for? Wait, was I the uninvited guest in someone else's abandoned house? No clue :)
There is one more thing- I don't know if unreal engine can do web builds (UE4 could do it I think), but if it can, do it. Way more people are gonna play your games if you do!