Other than positioning and being a little hard on the eyes, it's not too bad.
Postitioning:
Your red blood dripping bar is stuck to the left, and falls short of the page width when viewed on a wide screen monitor. Widen it to fit, or center it so it looks even would be the standard 'fix' BUT you are using %'s to space your images and content, so it expands to fit the monitor width. This makes your images run way wide of the layout you have set out on wider monitors.
I would look at defining the width of each column so that it stays fixed and not flowing with a user's monitor size. That will help keep your content in line and not spread out so far appart.
Colour:
The pitch black background is nice for the theme, but that purple background on the links section stands out so brightly in comparison. The white text is small and could be difficult to read for some viewers. I'd play within the Halloween colours (black, orange, red) and see if there is a better combination that stays within the theme. Not sure where the purple fits with Halloween, but maybe that's more of a local thing?
You have loads of links on the left. What about grouping them together, then offering sub-catagories once the visitor has chosen a catagory? Either via a 'drop down' menu or after the catagory has been chosen. That would mean your link list could be "Costumes" "Accessories" "Make up & Teeth" "Masks" ect.. Would leave more room to size the font up a couple notches. Right now, it's a tonne of reading/scrolling just to get a sub catagory.
Overall, a functional site with a theme that does work nicely on small to medium size monitors. Good Job and good luck with 'tweeking' it to something you really like.
E-Learning Specialist
www.mainsites.ca is my website, and yes, some of it is crappy.