No port forwarding required on hamachi. You may need to make firewall exceptions, though. It's been a few years since I used hamachi, so I'm out of date on their specifics. But it used to be that just using the hamachi address of the other person (5.x.x.x) would work for direct connect. But broadcast messages would not pass through, so not seeing the game on the listing on the LAN is normal.
Some other folks around here have switched to using other services like Tunngle for a variety of reasons, some not to do with our games I believe. I've just been port forwarding, so I've not paid too close of attention. Hopefully someone else using that sort of solution will swing by, but right now with hamachi my money would be on firewall.
Hope that helps!