Looks like you just want transparency.
It is possible to get transparency going with puppy, eg-
Or other linux distros with openbox (the desktop enviroment currently used by puppy)-
IMO puppy is too much of a pain, and I'd prefer other distros (like cruchbang or antix) for use on an older, slower CPU/small RAM system. They run better than puppy IMO, and are easier to find documentation or other info if you want to make changes.
If its not that old a computer, maybe KDE 4.X would be a better choice. Its got more 'eye candy' out of the box than the simpler lighter desktop enviroments.