spoilers:end of spoilers
Ywa I've actually seen two scenes with this character on the internet. first was Martha turning into Jonn after talking to Lois. Looked like awfull CGI. Them I saw one of Jonn talking to Bruce but it was grainy.
There also some Tweets being shared around of people who got to accidently watch it early. The ones I saw all were upset about the CGI throughout. Starting to think Bad CGI won't be isolated to a couple scenes but be sprinkled throughout.