Here are some general guidelines for setting up Crysis to work over Hamachi.
For more detailed gameplay info, see the Official EA Forums.
You need to login with your GameSpy ID first (as to go play on a internet game), or you won't have much luck connecting.
Per EA, the following ports are required to be open for the Hamachi network adapter in your software firewall in order to play a Crysis network game:
- 29900, 29901, 28910, 6667
- 64087, 29910, 27900, 27901
- 29900, 29901, 28910, 443, 80
These ports only need to be permitted in a software firewall when playing over Hamachi. Do not port forward any of them if you are playing only via Hamachi, as it opens a security hole into your network.
EA Forums on setting up a server