The rest of the game, with the exception of a few unit types you may have never seen before, looks just like every other Heroes III-based title. Interface, units, everything looks just the same. I've always liked the look, and to be honest I'm not sure how much it can be improved on, but I'm sure there's something that can be done to make it more interesting.
As for sound, don't expect anything new. The music and sounds should be familiar to anyone who's played previous games in the series, and the minimal voice-acting is the only real difference you'll note. If 3DO uses the same music in the next Heroes game, I'm going to crack some heads -- as good as it may be, there's only so many times you can listen to it before you get downright sick of it.