The level of difficulty in the Devil Whiskey can be increased or decreased in the game options settings. Or alternatively you could open up the .cfg files and modify the random monster encounter rate to your liking.
The game was designed to be similar to the old Bard's Tale games so yes it is combat heavy. If you liked the old Bard's Tale trilogy, then you will probably also like the Devil Whiskey.
If you didn't like the Bard's Tale trilogy, then you might want to look elsewhere, or try the demo first like you said.
Unfortunately Decklin (the guy now has the rights to the game), hasn't kept up with the website so there are allot of dead links on the Devil Whiskey site.
http://www.devilwhiskey.com/ You can obtain the most recent demo version and the mods+patches
here The game is still being sold at
Decklin's Domain Hopefully one day he will release the source code as was promised ages ago, but I doubt that will ever happen.