How to host a game so others can join? Why does nobody join?
You have to setup your router and firewall (if you have something like that). Carnage Contest uses UDP port 36963 by default. You can also use another port.
Please read your router/firewall manual for details.

Things to check/do/configurate:
- The Windows firewall (when using Windows)
- Your software firewall (if you are using one)
- Your router firewall (if you are using a router)
- Your router port forwarding (if you are using a router)
- Close other programs which use the internet / stop downloads