I actually like this a lot already -- you've shaded the holes well, and picked very nice cheese-like colors. And yes, the top did look like a crust. As for the process, it looks like your work flow went very smoothly, with efficient work stages, and with the detailing done in a good order to avoid having to re-do things unnecessarily.

I would only suggest that the 'sharp edge' at the front of the slice needs to be softened a bit -- it appears to be almost perfectly thin, being only one pixel wide.

Is there going to be a background? (perhaps a simple tablecloth with a complementary colour) If so, you'd get a chance to AA the top rounded outline, as well. Otherwise you may have to make the background transparent since Pixel Joint submission guidelines don't like blank backgrounds.

This is going well -- it's small but attractive.