Quote: "My favourite game idea was one that was under the working title "Extreme Post Mortem"."
Ah, I read that a while ago in geek culture. It sounds like an AWESOME idea. seriously. with a decent game engine and a good plot + ending, it could be a seriously amazing game.
My game idea is basically a free roam, apocalyptic, zombie-infested world. Basically, the player would roam around, and gather other survivors. Maybe even a group of 300-500. The player would have a large world to explore, with different areas with different severities of infection (possible with upgrades or something in the center). I could imagine transport by car, bus, or airplane, in a low quality world (think flight simulator), and procedural buildings (so as to be detailed, but also cover multiple cities). I would imagine that overall gameplay would go something like this:
1. player starts out alone.
2. player starts wandering, killing zombies and collecting upgrades/supplies
3. player starts finding survivors, and begins to build temporary field bases, still remaining nomadic.
4. player reaches larger party size (30-40 people), and begins to raid large zombie strongholds.
5. player may settle down, with 1 strongly fortified base
6. zombie invasions ramp up. with a larger party size (80-100), people may become infected more frequently
7. ...at some point, player faces gigantic zombie onslaught. May flee alone, fight and survive, or try to save others. Any ways, player either dies, or almost loses everyone.
Tie that up with a loose storyline, maybe different levels of zombies, cool upgrades, and cool barricades, and you have yourself an awesome game.