Well, the 2/9/16 episode of 'The Flash' was fun. In a rather moribund mid-season, hopefully "Welcome to Earth-2" is the spark they need to get the ball rolling up to May Sweeps in the U.S.
For those not following along, the Big Bad in season 2 has been Zoom. A black-clad speedster from a parallel earth, Earth-2, Zoom (an uncredited voice by Tony Todd) preys on other speedsters and takes their speed. He's basically a speed demon/vampire.
Since Thomas Cavanaugh's character Harrison Wells died last year, the producers brought him back as Harry Wells, his Earth-2 counterpart. Zoom is holding Harry's daughter Jesse hostage to force Harry to steal Flash's speed. Team Flash finally caught on and rather than lock Harry in a cell for good, said that they'd go to Earth-2 with him to rescue Jesse and defeat Zoom.
So this week's episode start off with Harry going to Earth-2 with Barry and Cisco. He warns them that they're entering a strange mirror of their Earth and advices them not to get emotionally attached to them there. However, before they arrive, they travel through the "multiverse" and catch glimpses of:
Supergirl (from CBS' 'Supergirl' series, and foreshadowing a Flash/Supergirl crossover on 3/28/16)
Old West bounty hunter Jonah Hex (scheduled to appear on 'DC's Legends of Tomorrow')
A future Green Arrow (also to appear on 'Legends')
Either an older Flash, or John Wesley Shipp as the Flash from the 90s 'Flash' series.
A Legion flight ring, belonging to the Legion of Superheroes, a teenage group that the time-traveling Flash and his descendants have often been connected with.
In the best 'Star Trek' "Mirror Mirror" tradition, once the trio arrives on Earth-2, they start meeting counterparts. A man they know as a villain is Harry's lab assistant. An assassin is an inept police detective. Captain Cold is the city's mayor.
You kind of wonder why Harry didn't mention some of this before, or react to some of it in the past. Like "Hey, this guy is the mayor on my Earth and you're beating the snot out of him here.") Also, apparently the budget wouldn't spring for anything major, so we get two minor villains as counterpart demonstrations. Couldn't they have at least brought Dominic Purcell in as Fire Chief Mick Rory?
Anyway, the real fun is when Barry and Cisco start meeting counterparts of their friends. Barry-2 is a nerdy police scientist. Barry's foster sister Iris is married to Barry-2 and a tough-as-nails police detective. Her father is a jazz singer who hates Barry instead of a police detective who likes Barry.
In a change of pace for Danielle Panabaker, who plays the mild-mannered Caitlin Snow, her counterpart is the villainous Killer Frost with ice projection powers. She's teamed up with Caitlin's dead fiancée on Earth-1, Ronnie Raymond, who now calls himself Deathstorm. They work for Zoom making sure all of the city's bad guys pay their dues to their boss.
Well, actually they work for Reverb, who turns out to be Cisco's counterpart. Reverb works for Zoom, and has developed his vibrational powers to point where he can shoot sonic blasts. After one well-filmed fight where Barry takes on Killer Frost and Deathstorm, it all comes down to a big showdown. Reverb offers Cisco the chance to join him. When he refuses, Reverb and Deathstorm take down Flash and prepare to kill him. Zoom... umm, zooms in and kills them for disobeying his orders to take Flash alive. This sets up Flash being taken captive and his friends on both worlds teaming up with Killer Frost (who just had her boyfriend killed) to rescue the speedster.
Back on Earth-1, the "real" Caitlin is working with Earth-2 refugee Jay Garrick to help him get his speed back so he can fight a new villain, Geomancer.
Overall, the episode was the most fun that the series has had in a while. Cisco's character is the typical nerd spouting movie and TV references, so he's well aware that they're in a mirror-mirror scenario and his evil counterpart is trying to "Vader" him into joining the dark side. There are other fun parts, like Cisco and Barry taking a selfie of themselves when they arrive on Earth-2. Barry reacting to his foster sister kissing him is amusing.
There are also a few other in-jokes, like the non-superspeed Barry-2 having "Bruce, Hal, and Diana" on his speed-dial. Panabaker seems to be having a ball playing a sultry super-evil villainess who will have the chance to come around be a reluctant hero. And Jesse L. Martin as Joe got a chance to belt out a few show tunes and also looked like he was enjoying himself.
There are also deep emotional moments like Barry getting to call his still-living mother on Earth-2. And Joe-2 dying a hero's death saving his daughter from Firestorm.
Overall, "Welcome to Earth-2" was a home run as an episode. Thomas Cavanaugh didn't have much to do and Geomancer didn't make a particularly inspiring villain. And Zoom still doesn't have much of a personality. But all of this is relatively minor, and swept away by the sheer goodness of the "what if my life had turned out different" mirror-mirror nature of the parallel Earth.