Empires of the Void II: My Favorite Mechanism

About Empires of the Void II, from BoardGameGeek:

The Kurross Empire emerged from the deep, endless pool of space, dark and undetectable. They crushed Earth's paltry fleet within a week, and broke through the great planetary shield that protected the surface. Bright blue oceans turned to an irradiated wasteland as they bombarded the planet, shredding the remnants of thousands of years of human history. Markan, last captain of Earth's forces, made a final, desperate attempt to survive, salvaging an abandoned Worldship from hundreds of years past. She took command and headed for the fringe of the galaxy, where there was a chance to gain a foothold, grow in strength, and find new allies for the fight against the Kurross. Earth's long-time enemies, the Zun and Decima Empires, soon followed in their own Worldships, leaving behind decimated worlds and lost family, determined to stake their own claim of the fringe. In Empires of the Void II, you have been given a mission to establish a foothold at the fringe of the galaxy for your galactic empire. The game begins when your massive Worldships reach the fringe, where you must explore, wage war, use diplomacy, and construct buildings to gain victory. The fringe is sparsely populated and the few local sentient species are struggling to survive, leaving huge regions of planets open for exploration and colonization. Many species are eager to ally themselves with a powerful empire to gain security and stability in a chaotic and difficult time. As you explore and interact with planets, you will discover unfolding stories of the fringe. Each inhabited planet is home to a unique alien species, with their own goals, values, and problems. Will you give aid by fighting off pirates, transporting goods, and curing strange diseases? Or will you invade and rule with a cruel hand? This may be your last chance to prepare before the Kurross meet you again.