This issue is fixed. Instead of just being an arse like others did in my searches, let me show how I've done it.
I've extracted the tar archive, and this is what's been done:
Extract the folder to your desired location.
Do "cd /<your location>/supertux-0.3.3/ && mkdir build && cd build/ && cmake ..
This will do the config. If you're missing any dependencies, add them from Entropy (or emerge).
before you start the make process, you'll have to create a symbolic link for curl, as it's going to look for curl/types.h and the newer version moved the types.h to curl.h.
So do "cd /usr/include/curl"
Then create the link with "ln -s curl.h types.h"
Go back to the build directory then start make. Do make install after and then it's done. For me, I have to run the binary from the source file, and it works great, so does the add-ons.
Hope it helps a few folks as well!
This should also work with other programs that are looking for types.h as well.