2. Star Blazers
The American adaptation of a Japanese series, Star Blazers is a pretty big concept overall. An alien planet bombards Earth with radioactive meteorites until the only place relatively safe from the ruined and contaminated surface is underground. The realisation that mankind has a one-year time limit until the damage is beyond the technology of a friendly alien race to repair forces humanity to follow the plan these aliens give them; build a giant spaceship around an incredibly powerful piece of strange technology, and push that craft to the limits of its endurance to reach a distant world. Once there, the ship must immediately return, carrying a terraforming cargo, or all life on Earth is doomed. With strong themes of death and loss and sacrifice, an adult understanding of the strain of conflict, an ever-present threat of humanity's extinction and a caution against use of environmentally devastating weapons of war, Star Blazers carries such a story with ease.
How This Could Work: If there's a mother of giant space battle concepts, it's this one. The Yamato regularly takes (and deals) colossal damage whilst running a defence against swarms of enemy fighters with banks of its own defensive guns as well as its own fighter craft. The Wave Motion Engine can be used for propulsion as well as staggering firepower. It's held together by a time-limited story arc. Crewing, research, resource harvesting, repair management and upgrades could feature strongly. However; in amongst the awesome destruction, smoke, flames and wreckage, it would be extremely important for the game to not lose the themes of the impact of conflict upon combatants, and the human cost of choosing to unleash annihilation upon other living beings.