Wow, this topic is really helpful and I hate it.
Magnetic spaceship collecting little magnetic doodads was my leading idea; collecting not goal scoring so completely different there.
What's worse is I also planned to add remote multiplayer, procedural levels and ai as technical parts to show off- I guess that won't cut it here.
My now leading idea involves changing (upgrading?) flocking into more ai driven boids how this will be a game I know not, yet. However it occurs that this is also pretty derivative I might even have to try the whole imagination thing, very annoying.