As a total final, there could be animation of the flying away on the restored Crashed Ship.
It was slowly regenerating, and after the Prottos have been defeated, the regeneration is finally over and everyone is loading in and travels to some attractive place.
There could be an option to load all your units to the ship and take with you, so there some sequel could start, like an extra mission (it can be positioned as the original one, interrupted by a crash)
And access to this mission at the moment of completing and for the future can be granted only for those who completed the entire first part at least once.
It was slowly regenerating, and after the Prottos have been defeated, the regeneration is finally over and everyone is loading in and travels to some attractive place.
There could be an option to load all your units to the ship and take with you, so there some sequel could start, like an extra mission (it can be positioned as the original one, interrupted by a crash)
And access to this mission at the moment of completing and for the future can be granted only for those who completed the entire first part at least once.