We knew Mads Mikkelsen was playing Galen Erso but this is the first time we see him as he tells his little girl, "Jyn, whatever I do, I do it to protect you." Fathers have always factored big time into Star Wars films — Anakin Skywalker, Han Solo, etc. — and Rogue One is no different: Galen is key to the Empire building their planet-sized weapon of mass destruction, the Empire's Director Orson Krennic (Ben Mendelsohn) seems to know him very well, and Galen's presence in this situation is one of the reasons why Jyn signs on to help steal the Death Star plans.
That was readily apparent to pretty much anybody who saw it in the original Star Wars but the sizable superweapon is seen here on a cloud-covered horizon looking more menacing than ever. (It's no Starkiller Base, but still.)