The official description for Ep 17 "Flash Back" I've edited some of it as contained spoilers:
A MOMENT IN TIME GETS BARRY ONE STEP CLOSER TO ZOOM; ANDY MIENTUS RETURNS AS HARTLEY RATHAWAY – After the shocking revelation that Zoom is ..............Barry (Grant Gustin) is more determined than ever to get back to Earth-2 to stop Zoom forever. Desperate to find a way to increase his speed, Barry decides to travel back in time and masquerade as his earlier self in order to get his arch-nemesis, Dr. Harrison Wells/Eobard Thawne (Tom Cavanagh), to teach him how to run faster. However, things don’t go as planned and Barry is stunned to face familiar foe Hartley Rathaway (guest star Andy Mientus), as well as old friend ...........Iris (Candice Patton) makes peace with her past in order to embrace her future.
"The Reverse-Flash Returns", one of my fav Ep's of season two it's always great to have the reverse flash as you know and I did say he would be the same reverse flash from Earth 1. As you would have seen the Ep served as a origin story to reverse flash because his a younger version of him they can bring him back at any time. I loved the fight between Flash and Reverse Flash and race at the were end were Barry sends reverse flash back to the future via worm hole and even pushed him through it lol.
The origin story of Reverse Flash is exactly like how it was in the comics which pleased me after the Ep, also you get to see Jay Garrick's Earth 1 counter part but his name is Hunter Zolomon now in the comics there is a big story to do Hunter Zolomon which I won't go into as it may serve as a spoiler but if they do use him then where going to get a exciting end to Season 2.
The only Easter Eggs i saw was Hunter Zolomon and the cosmic treadmill which the Flash used to use in the comics to travel through time. Other then that fanastic Ep.
Been hearing rumours that if the Supergirl crossover is succusseful then next season Supergirl might appear in The Flash which has been easier as CBS has a new president plus Time Warner own a small part of CBS and Cw and it's written by the same people.
My theory on how Barry crossover is I think his either gonna try time travel again or try and cross over to Earth 2 and it's gonna wrong as it always does and we'll probably see it happen at the end of Ep 16 which airs on the 22nd of March.
Grant Gustin has hinted that we could be seeing all four shows crossing over at some point.
I think it is not earth 2 but a different version of earth where there are aliens.
the feel of earth2 is a mix of 1920/40s and the future.
It's quite clear that it's not Earth-2 as there's no mentain of either Superman or Supergirl and vice versa on the Supergirl show, the only reason why it has a different look to it i.e a Art Deco/future look to it is to tell the different earths apart it's also why Earth-2 has colour saturation drained look to it Smallville did a very similar thing in Season ten when Clark crossed over to alternate universe and they just saturated the colour to tell the earths apart.
My theory as i said in what is gonna happen is his probation gonna try to get to Earth-2 which I won't spoil why you'll work out why in two weeks time on sky and similar to how he accidentally time travelled in season one when he tried to stop that tidal wave his gonna accidentally cross over into alternate Earth namely Supergirl's Earth.
Inside: Trajectory Ep 16, The Flash returns in the States this Tuesday, watch out for the last 5 mins for something really special got a feeling I know what that is
http://youtu.be/QeYSUCs9DBk
Watch out for a ton of Easter Eggs in Ep 13 "Welcome To The Earth-2" which is a two parter all I'll say is watch the wormhole and a telephone, second part "Escape From Earth-2" airs next week on Sky.
^^^
Just watched it on sky1 & got all the Easter Eggs you mentioned for Welcome To Earth-2. The comic book geek in me let out a little squeal when I saw the Easter Egg in the wormhole as Barry & team flash travelled to earth-2, then another squeal when I saw the phone. Also loved evil Caitlin Snow/Killer Frost
Best episode of season 2, possibly best ever episode of the flash.