burning people is more fun than burning objects.
if you don't want death you can have people reacting to burning. example: burn things in a way that make people react. imagine some simple puzzle game. you have the people. they are AIs: very simple. they react in different ways to different things. they are kind of like lemmings. maybe they:
. stand near fire when cold
. are attracted to sounds far away
. are afraid of large explosions
. run for safety when their environment is set on fire, and try to run away from the fire.
-> see how like lemmings? light environment on fire in specific ways to create chain reactions that then drive the people around.
. change dramatically when friends die in fire
. try to kill each other with fire if stressed.
player can try to save people, or make them accomplish something, or weed out the bad ones and burn them, or burn the attacking monsters and protect the people etc.
I like it. I really do feel this is the way to go. But hording the people to an exit seems to easy. I'm thinking of a platformer with people running around in whichever direction, and by the use of various elements and tools - such as fire, you clear their way.
For example there could be a big boulder in the way, and you'd have to use fire crackers to blow it out of the way. Or there could be water in the way and you'd either have to turn it into steam (using fire) or freeze it to ice.