we only have one glass effect - and one metal effect. some more would be useful 
OK Mattn - I thought the glass breaking sounds would be easiest to produce and I figured you would have had loads of submissions by now.. but I've already set up quite a few - I'll re-visit and create the .oggs.
In the meantime I've attached the Metal Breaking effects - although they don't really sound like breaking - more clattering and banging, but it's the nearest I could get without spending a deal of time - see what you think
