So this theme is pretty hard, but I think I've finally got an idea.

I dunno what other people think about sharing your ideas on here. But these are the ones I came up with (and am not using)

First: An ecological game, something where you're looking at the habitat of the Polar bear (because their environment is ice, snow and water. Pretty darn easy art me thinks.

Second: Text based action game, you're given scenarios and you have to avoid hitting things in the scenario. if the scenario plays out that you make the wrong choice too many times, you run out of space and hit a wall or something.

Third: Hehh.. actually just thought of this, isn't chess a game about running out of space? I mean really when your king runs out of space, your king is dead. That's chess. I guess that's a different kind of checkmate, where you take all the players pieces so they can only move their king, then you make it so you corner the king without actually putting him in check. But I don't really know chess well enough to know what that's called.

Forth: A tower defence game, but instead of having mobs come directly at your base, they are more like a "zerg" fungus, where they just keep taking ground away from you. Eventually you run out of ground unless you defeat the fungus and knock it back enough that you've got it controlled. <<< Mechanic I thought of to go with this, make the fungus a "plant" so you can make it effected by weather. So if it's raining, the plane will grow more vigorously, if it's sunny it will grow more vigorously. I would use Perlin noise to generate two waves/signals, link one into 'water' and one into 'sunshine' so the veracity of the fungus is repeatable (use a seed!!!)

Anyway, I hope everyone else if having fun, and if you have not thought of a theme, I hope this post might have given you some insperation!

Good luck Y'all