I had original Demo version which I lost back in 2008. But anyway, I found a difference with Full version and Demo:

When you touch the smokes of caterpillar in the demo version and get dizzy: the screen hue changes continuously in a smooth fading way. But I never saw this in Full version [I can't remember about original Full version as I lost it and now I've a downloaded copy].

Edit: Sorry for reviving an old thread, but I find no reason to make a thread for only one simple thing.