For Still Life try
GameExtractor, it is said to be Still Life compatible, maybe it can open .dlg files as well.
The Runaway files look either encrypted, or some odd file formats with their headers cut off. No easy way to open those, I'm afraid.
For Broken Sword, try
this (taken from a Russian site, from a patch for a crack for the game). Don't blame me if it blows up your PC.