My biggest problem at the moment is holding myself back from commenting on everyone's ideas. I've posted a few general vaguely encouraging comments, but I'm not sure if it's proper to start handing out advice or publicly laud ideas as fantastic; I am going to be judging these things next week. To summarise though I'm impressed with everything I've seen so far; I'm actually surprised with the creativity being shown with the tower theme.
I'm afraid I don't have a lot to report myself; I've only spent a bit of the time brainstorming, but then a bit more time playing Rome: Total War for the first time. Unfortunately Dungeon Siege 2, the game I've been gradually playing the last few weeks as it's so mindless it's completely unaddictive and perfect for when I can't think clearly enough to do anything, got too boring for me to continue (mindless can be a virtue, but not if the game is so long and bland). Next on my list of PC games was Rome: Total War, but I should have known better than to try out a game involving tactical combat and ancient civilizations. I might have to put that in the same pile as Civilization 4; too dangerously addictive to play [tears].
So far all I've done is a few sketches and an attempt to see whether a graphical effect would work with a simple extension with the Brixtar engine, which it didn't. Currently all I know about my idea is:
- it will eventually involve at least one tower
- since I don't have to worry about the judges understanding the game, I might as well go for a high level of surrealism
- There may or may not be polka music involved
Just regarding your depth-sorting issue: After reading your previous comment about how almost all of the sprites have alpha on them, I had one more thought about what you could do. You could try assigning your sprites to different depth "layers" (like in photoshop). Then you can just shove whatever sprites need drawing into the "bucket" for that layer and do whatever sorting is needed (if any) for that bucket. It should keep the amount of sorting needed to a minimum. Here's an example of a set of layers you might need (in a layers array) for a hypothetical 2D platformer game:
layers[0]: Background
layers[1]: Parallax scrolling background layer 1.
layers[2]: Parallax scrolling background layer 2.
layers[3]: Parallax scrolling background layer 3.
layers[4]: Platform geometry layer.
layers[5]: Foreground characters layer.
layers[6]: GUI/text/etc display layer.
The layers would be drawn in order. You may want to sort some layers and not others (if you know that the sprites in that layer won't collide).