Excuse me if this seems a little jumbled up but I feel I have a pretty sound theory on who Zoom might be and I want honest feedback.
"Escape from Earth 2" has succeeded in leaving us with even more questions. Most of all, who is Zoom?
In the episode there were quite a few things that altered my one time belief that Henry was in fact Earth 2's Zoom. From Jay's disappearances in the show to the man in the iron mask being upset that Barry couldn't understand his reference to Jay and many other little tidbits of info I've gleaned from the show. So, without further gilding I will tell you my opinion.
Jay Garrick as we know him is an impostor. Looking back at the shows other doppelgängers they have all had the same names, Cisco is Cisco, Caitlyn is Caitlyn, Barry is Barry etc. except for Jay. Jay's earth 1 counterpart is Hunter Zoloman (which we comic fans know is actually Zoom in the comics) which sat with me weird when we were first given this info.
So, what I assume is that the man in the mask is actually "THE REAL" Jay. This would mean that the "Jay" we know is actually Hunter from Earth 1 and Zoom is Hunter from Earth 2 and they're working together. After all, since "Jay" has been on Earth 1 he has been looking for ways to be faster, a goal much like Zoom's. I believe "Zoom" (Jay) is working to steal speed from other speedsters and "Jay" (Zoom) is looking for other ways e.g. Velocity.
I know this leaves a lot of questions like the fact that all of Earth 2 knows Jay is the Flash but that only begs how long has Zoom been posing as him. After all, Jessie said the masked man was there before her. So, let me know what you think.