VC 6
In Visual C++ 6, how are you supposed to compile it?? You can use the source code from the DEV C++ DevPacks, but you still need the Visual C++ 6 Libs. (Libraries)
For people having trouble compiling, I recommend you get Visual C++ 6 or higher and the SDL source code, DLLs and Libraries. It seems to be easier, but it makes SRB2 a little bit different. Sound sounds crackly, and is quieter and it has a weird window that's like when you run a dedicated server or something, except it's always there.