Does it support higher fidelity/quality pixel art? For example, something that looks closer to B/W sprites and tiles?
Yes it's very very possible^^ We are working on creating a couple of demo's (or at least a demo reel) that shows many different types and styles of games that can be made with MonMae, however currently all time is being put into new features and making things easier for the less code-savvy users.
An intermediate user could make a B/W style game quite quickly and easily using MonMae, as swapping out the art is a process that could be done in only a day or two.