@Zhukov44:
Say I have a transport with 2 inf on it at the start of a turn. In Global, can you offload 1 unit as a combat move or do I need to unload both inf at once?
Yes, if that unit was already on the transport at the beginning of your turn.
If so, does it make a difference if the infantry were already on the transport?
Yes. If you had picked both of them up in the combat move, then you would have to amphibiously assault with both of them. If you had one on at the beginning of your turn, and picked up one in the combat movement phase, you could also assault with only 1, which would be the one you just picked up. You could leave the one that started the turn on your transport, on your transport while amphibiously assaulting with the one you just picked up.
Page 16, under “transports”:
“If a transport loads land units during the Combat Move phase, it must offload those units to attack a hostile territory as part of an amphibious assault during the Conduct Combat phase, or it must retreat during the sea combat step…”
Page 33: “During an amphibious assault, a transport must either offload all units that were loaded during the Combat Move phase or retreat during sea combat. It can also offload any number of units owned by the transport’s power that were already on board at the start of the turn.”