Reviewed by Louis Rabinowitz.

Since Atom Smasher ominously told Barry about the threat of Zoom back in the season premiere, The Flash has slowly been building up our knowledge of this alternate universe, Earth-2, from which Jay Garrick and Harrison Wells have come. With Barry having buried the hatchet with Wells last week and agreed to help him save his daughter, it was time for The Flash to make good on that set-up for its first trip to Earth-2. Did this long-awaited episode deliver on the considerable hype?

It pretty much delivered. Welcome to Earth-2 sees The Flash return to its freewheeling, exciting and emotional best for an episode that makes the most of the huge potential that Earth-2 provided. The episode exploited its setting in numerous, excellent ways, but it’s probably worth mentioning the mountain of Easter eggs and fun nods to the DC canon. From the sightings of Supergirl (especially pertinent given last week’s crossover announcement) and, absurdly, John Wesley Shipp’s short-lived 90s Flash in the multiverse to Earth-2 Barry having people named Bruce, Diana and Hal on speed dial, Welcome to Earth-2 went up to eleven with the types of fan-pleasing visual gags that The Flash could only portray in this unique setting. It’s a small thing to congratulate, perhaps, but there’s an evident love for the DC pantheon on display here from the writers and an admirable desire to hint as heavily as they possibly can at characters and locations (Atlantis also got a namecheck) that are exclusively reserved for The Flash’s showier big-screen counterparts. Also, this episode gave us hints at ‘Mayor Snart’, and that alone justified Welcome to Earth-2’s existence.

Part of the fun of alternate-universe stories is the juxtaposition between the familiar characters we know from our universe and their drastically different alt-universe counterparts. Welcome to Earth-2 doesn’t pass up the opportunity to place a whole host of familiar faces from both The Flash and Arrow into unexpected and frequently hilarious new roles (my favourite was probably alt-Deadshot, the worst at marksmanship in the CCPD). Not only is it very enjoyable to see Joe as a lounge singer and Iris as the cop who rejected a job at the paper she works at in Earth-1, but there’s also substance behind these novel counterparts wearing familiar faces. The script manages to carve out distinct and unique personalities for Earth-2 characters such as Iris and Joe that display just enough difference in demeanour and outlook to feel genuinely different from the characters we’re familiar with as viewers, but equally, the counterparts are kept recognisable enough to underline the point that these are fundamentally similar people who have simply been influenced by different environments and circumstances, and have therefore taken a different path in life. A great deal of this impressive balancing act between novelty and familiarity is down to the script, but the versatile work of the cast must also be highlighted as a key factor – Candice Patton and Jesse L Martin really rise to the challenge, making these counterparts convincingly different enough so that they don’t feel like the same character in old-fashioned clothes.

On the villainous side of the equation, Welcome to Earth-2 served up more doppelgangers with the villainous duo of Killer Frost and Deathstorm. It’s Killer Frost who quite rightly gets most of the limelight here, with Danielle Panabaker giving a far more dynamic performance than her frequently prosaic material as Earth-1 Caitlin allows – if Panabaker’s performance as Earth-1 Caitlin is all good natured, buttoned-down conservatism, then there’s a palpable sense of joy and freedom to her performance as Killer Frost that indicates she’s relishing the chance to play a villain that’s been teased since the season one finale. Deathstorm’s pretty middle of the road in comparison, with Robbie Amell delivering a performance that’s just a few clicks north of his usual portrayal of Firestorm, but the relative blandness of his performance is mostly cancelled out by the briefly mentioned yet chilling idea that this version of Ronnie has completely subsumed Stein, who’s become a silent prisoner in Ronnie’s head. It’s a brief line, but it manages to make up for Amell’s blandness somewhat by adding a characteristic to this evil version of Firestorm that has genuinely disturbing implications.

If Killer Frost and Deathstorm were mainly included in order for The Flash to have a bit of fun with a ‘what if?’ scenario naturally provided by the setting, then the other villainous doppelganger, Reverb, linked in more directly into his Earth-1 counterpart. It’s obviously a lot of fun to see Cisco stumbling over his words when confronted by his surprisingly badass counterpart, but Reverb’s appearance acts as a great way to push Cisco’s development as Vibe forward in a way that’s genuinely fun and organic to the story. The impressive display of Reverb’s considerable powers clearly shows that The Flash has barely scratched the surface regarding Cisco’s power-set, providing considerable impetus for Cisco to continue on his road to becoming a bona fide superhero who can hold his own in battle. With Reverb, Welcome to Earth-2 gets to indulge in the fun of seeing two drastically different lookalikes come face to face while pushing forward character development in a surprising and unexpected way.

Perhaps the greatest success of Welcome to Earth-2 is that it provides a strong character arc for Barry. The Patty conflict may have been wearying viewing, but it’s worked as a way to push Barry into a position where he’s slightly adrift in his normal life, leaving him open to becoming overly attached to a world that’s seemingly better than the one he left behind. This is actually a slightly stronger take on the concept of a hero’s ‘perfect world’ than Supergirl did in Monday’s episode, because Welcome to Earth-2 provides a balanced and nuanced conflict for Barry – while Earth-2 Barry is in a loving marriage with Iris and has a full, alive family, some relationships that Barry treasures aren’t as strong over in Earth-2, such as a version of Joe who’s mostly disdainful of him. Welcome to Earth-2 compellingly illustrates Barry’s sadness and temptation when confronted with this initially idyllic alternate world, most notably in the terrific scene where Barry phones his mother and confirms she’s OK. Grant Gustin expertly nails Barry’s conflicted mix of utter heartbreak at the fact that he’ll never get to have these normal conversations and joy at the fact he can still talk to the mother he had to let die. Yet despite this temptation, The Flash underlines the fact that a perfect, idyllic world simply won’t exist – while some areas of life may be better, there’ll be an equal amount of things that are worse than before; notably, the episode never shows Barry being tempted to actually stay permanently in Earth-2, even if he does steal his counterpart’s identity for an overly long period of time.

Over in Earth-1, Jay took centre stage for a subplot featuring meta-human Geomancer, who terrorises the city while Barry is away. As a vehicle for getting Jay to reveal his sins and require the further usage of the Velocity drugs, the Geomancer subplot was fine, and pretty inoffensive – it’s hardly the most exciting part of the episode, but it serves its purpose, with most of my niggles about the lack of development for Geomancer alleviated by the fact that he’ll return next episode. This subplot did have one ace up its sleeve in the form of a genuinely intriguing twist for Jay, as it’s revealed that his illness is the result of taking Velocity-6 in order to try and become faster. The idea of the inadequate, inferior Jay Garrick learning to equal the heroism of his more powerful Earth-1 counterpart is just about the only compelling, original angle The Flash has found with Jay this season, so it’s encouraging to see that The Flash is doubling down on that idea by taking Jay on something of a hero’s journey in this two-parter from powerless, inadequate schmuck to a heroic speedster once more. Welcome to Earth-2 takes the first steps in that direction, seeing Jay suit up in his Flash outfit for the first time since he originally appeared – though his burst of speed doesn’t last long, it’s pretty awesome to see the Golden Age Flash kitted out and fighting bad guys as he should be.

Welcome to Earth-2 also left us on a mighty cliffhanger as Zoom killed off two of his disobedient minions before kidnapping Barry. It’s a great ending that firmly re-introduces Zoom’s ruthless nature with the brutal, abrupt way he kills villains wearing very familiar faces, as well as speedily pushing forward the Zoom arc, which had been moving at a crawl since Barry’s first battle with the evil speedster in episode six. Zoom is still an imposing foe, but The Flash has kept him at arm’s length for long enough. Barry’s imprisonment in Zoom’s lair is a really exciting development that finally guarantees some face-to-face time with this year’s Big Bad that promises to reveal information about Zoom’s motivations (and maybe even his identity) that’s been completely kept from us until this point. That face-to-face talk, and the identity of the mysterious masked man also imprisoned in Zoom’s lair, will have to wait til next week – but that’s not a bad thing, because it means we’re not leaving Earth-2 just yet…

Rating: 9.5/10

Welcome to Earth-2 is the best episode yet of The Flash’s second season, making terrific use of its setting to deliver a great character arc for Barry and a fun array of doppelgangers and Easter Eggs, topping it off with an excellent cliffhanger that promises major revelations to come in next week’s episode, Escape From Earth-2.