Hello, parents of Anikan 911.
All port forwarding does is redirecting the connection of ports to specific network addresses.
So basically, if you port forward Blockland, you make your router connect to the master server through a port (port 28000 is the most common.).
Port forwarding does not open your Internet to hacking because it has nothing to do with your firewall or security.
Port forwarding, if done correctly, is completely safe.