Idea 1)A true Zombie Apocalypse game. Not just another flat shooter.
The game would focus on surviving the zombie apocalypse. Having to fight to survive, find shelter, food, ammo as well as hold on to you sanity.
Players have the ability to flee across the country from the zombie horde or try and rebuild the shattered world. Go it alone or save survivors, or just take advantage of them.
Hundreds of story lines and plot archs about what happened when the zombie apocalypse went down. Links to how it happened and maybe how it can be stopped. Random content buildings so your not stuck rummaging through the same damn layout over and over. Total freedom in choice of your actions. Can only save in safe zones but can use a note save system to save anywhere if you need to just to raise the stress level up. Day night mode based on real world time.
Friends can jump in and out at any time. Online multiplayer as well as four player offline.
Idea 2) Tactical FPS/RTS hybred. Lead your troops into battle.
Essentially a fps but with a click of a shoulder button you can give commands to troops in the field. Organize your troops, train special ops troops tailoring them to your specific desires. Manipulate gear and battle positions. Be part of the action while sending out orders.
While my Original idea is SCI-FI(Cyborg Army versus Radiated mutants versus Reptilian monsters)I am sure many other genres can fit.
My continuation of this is it would have a massive online component where players fight for territories on a massive over world map. Players from all three sides can battle for a territory, last man standing wins. Once a side takes over players or factions(guilds but with shared resources) can construct and modify territories to suit them. Either by building defensive structures(walls, mounted guns, fortified bunkers) as well as training troops, or maximize resource potential by focusing on the economy.
I have more ideas and this is just the bare bones of those two ideas. I can go on for hours about these and more.