Marty Feldman did not receive an Oscar nomination for portraying Igor in Young Frankenstein.
Feldman slinks around in the film much like one would in one of those old movies, and even says yes master constantly as well. Aside from the yes masters and the way he scurries about this is a completely comedic performance. His performance mostly consists of little humorous aside to the main scene whether it is a look, or a strange comment that he makes about something about himself, or some sort of slightest pestering comment against Dr. Frankenstein.
Feldman handles his very specific role, and most of his little reactions, and quite amusing, and many of them are hilarious. Feldman has quite a bit of fun having the dichotomy of the look of his character which is very much that of the 30's monster movies, but with an entirely modern manner in his portrayal of Igor's personality. It works quite well for the part, and Feldman certainly creates some of the highlights of the film.
Technically speaking his character is the most constant in the film as his role is quite firm which is making funny and bizarre observations throughout. Feldman makes the most out of all his moments though and they are terrific. One little moment I particularly find hilarious is his remarks about what his father said in times of distress. Feldman gives an entertaining and enjoyable comedic performance in the film that hits just the right notes.