This is how we decorated our lounge for our Murder at Horror Castle game which we ran as a pre-Halloween party (on the 1st October) so that we could test it prior to the Halloween season.
I wanted to create the spooky factor without using the normal blood-splattered freezes.
Spooky Entrance to Horror Castle
The square divider between our dining room and lounge was made to look like a castle entrance with three large sheets of cardboard painted and cut to look like the stone archway entrance of a castle.
Tip: by mixing purple and black paints, I was able to visually tie these cardboard stones in with the purple decorations used elsewhere; the result was menacing but warmer than just black paint.
To "guard" the entrance to this fearsome castle, I wanted the even more fearsome figure of the Grim Reaper. I got a second-hand Grim Reaper Halloween costume and ran a stiff cardboard tube through the arms to make them extend. Then I used garden string to suspend the costume from a nail in the wall above the lounge opening. To make the head, I used a balloon and added an old skull mask. Then I added a plastic scythe to complete the look.
On the other side of the arch, I covered bookcases with black sheets and then suspended a witch outfit from the ceiling.
Tip: white creepy cloth placed behind the witch outfit makes it stand out more.
Horror Castle - Made Out of Cardboard
I created the entrance to the castle using a wooden frame (for stability) and then stapling on sheets of cardboard. I then cut out the door, windows and top battlements and painted on bricks.
Rather than creating a drawbridge, I decided to use black chainmail (strips of black cardboard sellotaped together) to create a more menacing effect.
A huge black spider (a key part of the game storyline) perches above the entrance. Extra spookiness was added by hanging some Halloween masks behind the windows and then half-covering these with creepy cloth.
As a backdrop for the castle, I bought two grey sheets and painted bats, trees, the moon and dark clouds on top.
Tip: Using grey sheets as a base reduces the amount of paint needed to create a dark, forbidding backdrop. Mixing purple paint in with the black for the bats and the clouds visually tied the colours in with my other decorations. Likewise, adding streaks of orange to the trees tied the backdrop in with the Halloween theme.
For a little bit of extra spook appeal, I hung sheets from the ceiling and slashed the ends to create a tattered look. I used a permanent marker pen to paint eyes and a mouth onto a blown-up balloon and then added a balloon light for a faint eerie glow. I also cut up some old Halloween costumes that my children had grown out of and hung these over balloons to give the impression of figures "hanging" from lights.
With the lights off, the castle looks even more creepy:
The castle created a great backdrop for our party: