I admit it – I already had a game idea coming into this compo, and then I took the theme and merged the two.
Here’s a retrospective post on how that happened…

A bit ago I read an article somewhere (possibly on the excellent www.designer-notes.com) mentioning that Civilization’s combat is actually it’s weakest point.
There’s not much strategy in the actual fighting – it’s mostly making sure you have a ton of decent troops in the area.
This set me thinking – how could you make the combat in (the excellent!) Civ 4 more strategic? Could you add flanking into something like Civ? I thought if they got that working for Civ 5 it would be totally awesome.

Then came Ludum Dare 18, with the theme “Enemies as Weapons”.
Bugger. All my thoughts of doing an abstract arty game with no baddies, no guns, and no nothing went out the window.
Probably for the best – I’m no artist.
How about a platformer where the baddies have guns, and you don’t – you have to move to the baddy and then can use their gun? For extra depth, maybe you have to get behind them before you can grab them & their weapon?

Could be good. But I’m already making one action game… I want to make something different. Something more like….. Civ? Bing! The two thoughts came together in a crazed shotgun marriage fuelled by ginger tea:

Civ with flanking, where you grab baddies from behind, and then can use their guns

You can see that my final game differs from this in places… but that was basically how I started.