when I try to download the demo I get almost all the way through but at the end it says "The application could not be installed because the AIR file is damaged. Try obtaining a new AIR file from the application author."
how do I get it too work ???
You can try to download just the air file and install it:
http://knucklecracker.com/creeperworld/demo/CreeperWorldDEMO.air
You have to have Adobe AIR already installed, then you can just double click the CreeperWorldDEMO.air file to install it (after you have downloaded it).
You can get Adobe AIR from here if you don't already have it installed:
http://get.adobe.com/air/
If this doesn't work, then reboot your machine and try it again. Doing these things should get you in business.