How on earth does that have 256 colors? O_o beats me...
The castle idea is very cool IMHO, but the coloring needs some improvement. Since it's very late I'll skip in-depth critique right now, but I'm going to keep an eye in this one. Just a small suggestion: Try checking the image again, I don't think there are 256 colors there and if there are, it may be due to some auto aa or something like that. What software are you using for making these, Lancelot?