One of the things that killed some of the immersion for me was how Jaafar looked like Michael in one scene and not in the next.
Like, everything in the Off the Wall and Victory eras looked spot on, but it was the Triumph/Thriller period inbetween that I found disjointed.
For instance, on the way to Beat It rehearsal in the car I thought Jaafar looked really uncanny and strange, but then he looked great during the actual rehearsal scene. Same with Thriller - he looked great as zombie Michael but terrible as normal Michael