I hope that this hasty thumbnail sketch does justice to my current thinking for a mutant/zombie survival game.
Essentially I want yet another excuse to fill the screen with cannon fodder. Our hero sits central protected by fragile barriers and the monsters advance toward him (or her) from all angles.
Some zombies drop goodies and bonus items but most don’t.
Using the touchMove controls I want the player’s character to swing through 360 degrees. The moment the finger touches the screen the hero opens fire. Toying with the idea of a crosshair just now. This may or may not negate the requirement for on-screen bullets. I’ll implement them both and see which feels right.
To draw the monsters in the correct order I’ll run through their y-position and draw in order from low to high. This of course includes our hero and his barriers as well as all bonus items.
Finally (at least for this round of thinking) I’ll preserve the central floor area for a muzzle flash effect.