This is a room I made for halloween. You can also buy some of the assets seperatly from my profile but buying the room includes more assets and it has almost the same price. It seems like it has lots of polygons but it is because I made the wall and floor from pieces. If you remove all the floor and wall, the polygon caunt will decrease to 13k.

Note that the room has fog shader in the fireplace which will not work in your game, and it has a glass shader which will only work with cycles render engine.