Nothing wrong with that, it should turn out pretty well because then you'll know if something "isn't right"... if it doesn't work in context of a DnD campaign it probably wouldn't work in a standard RPG..

As to releasing an unfinished game - don't, unless you're not planning on working on it ever again. Once it's released, you'll have no real reason to clean it up to be released again - the first release seems to be the most important, for programs as well as games.