I kinda liked the crazy eyes after I got this far, so I didn’t fill them in.
Biggest issue is I made his chin way too large. So, it looks like a merger between Oppenheimer and Indian Jones.
That said, I do like the expression. It gets at how I think about Oppenheimer’s personality. Thoughts?

The cigarette doesn’t look right. It looks too 2-D. Perhaps it’s b/c the lips don’t appear to be responding to the presence of the cigarette appropriately?
A little shading of the cig will give it a cylindrical appearance. What gets me is the size of his pupils. It’s like he’s looking at a very bright light…like an atomic blast or something…hmmm
Very cool, nice work.
Never mind the cigarette or the chin. Eyes are great. Well done.