I like the concept, and I already thought that there was a game missing for this parody...
Most did say already the important stuff about the art, like that it should be getting better (is of course just concept art), but it has already good proportions, except some details (already mentioned).
My question is, if you do the original 2D color style, or go for a more 3D style with shadows and all like that you did with the Vickiy concept (well, for porn I guess the 3D one could be better, as it can offer more depth).
A problem with that could be partly the background, as you should keep in mind to edit it to match it to be more to the style.
But well, what do I know about art?
I would agree with an earlier post about wanda and her human look, that it somewhat doesn't fit if it is a parody, but maybe Timmy could have just done a wish for it, and maybe there could be an option in the game to reverse it for one or several scenes, or the other way around, that he can wish for the human form after some progression (but seriously, pls some scenes with the original form).
About content, most was already said as well, it being a corruption game and all, but maybe there could be some additional content with characters that don't get a full implementation, like making a wish for it to just do it, just as additional content or in an easteregg style mechanic.
If I didn't forget something, that would be all from me for now...