I didn't realise you'd put a lot of effort into art already. An inconsistent style can work in a game if the setting is suitable for it. (i.e. lots of disparate locations) Any game set in a particular locale (say a city) needs to maintain a regular look for that locale (even in comparing rough locales to the areas of high society the art needs to look similar)
For a game that uses a wide variety of art styles and gets away with it you should check out
The Museum of Broken Memories This exhibits a high details style for the central area but a variety of different approaches for each of the room's puzzle areas. Might make you reconsider chucking a load of work if the same basic approach would work for your idea.