Final Conflict (1997)

You're about to engage in galactic war like there's no tomorrow. Fail and there won't be one. It's just you against the Donanji Marauders, the most lethal aliens in the universe. But if you take them on too soon, you can kiss your little Alliance good-bye. Better get your ships together. You've got planets, moons, space stations and bad manners to conquer. Crucial resources are spread over 21 uniquely designed missions. The good news is you decide your own path.