We talked about this one some time ago, it was released as a freeware, now the author is about to release a commercial version, so if you liked the game and want to support the author buy a copy of the commercial version, meanwhile here the demo of the game.
The Freeware Edition:
Desktop Dungeon v00.51
2.8 MiB - 331 downloads
Check the author site for newer freeware version, macintosh too and of course to buy the game