I am – Hercules!!
Entertainment Weekly gives it an “A” and says:

… It's good. Really good. Like season-one, stuff-gets-answered, can't-wait-for-the-next-episode good. …

USA Today gives it three and a half stars (out of four) and says:

… Best of all, tonight's return is designed to start moving the story off of The Others' island and back to a beached ensemble that has been much missed. … As Lost episodes go, it's a good outing …

TV Guide says:

… The mystery deepens, the plot thickens, and — most critically and thankfully — the action takes a mighty leap forward as Lost makes a welcome return … riveting …

The Los Angeles Times says:

… for now, I'm operating on the theory that the producers concluded, over mai tais one night in Hawaii, that absolute certainty, in art as well as life, is overrated. I quite agree …

The Chicago Tribune says:

… As Benjamin Linus, who's apparently the head of whatever wacky experiment is taking place on the "Lost" islands, Michael Emerson has given us a complex and calibrated performance that mixes creepiness, intelligence and a twisted form of charisma into one quietly frightening package. And as Juliet, Elizabeth Mitchell has been a wonder. … Mitchell makes Juliet's steely resolve and her carefully hidden vulnerability fascinating, which is some feat. Right now, Juliet's by far the most interesting woman on the show. …

Variety says:

… even with flaws, "Lost" remains one of TV's zestiest stews. …

Scripps News Service says:

… It's far too soon to say if "Lost" has returned to form. But judging only by the opener, it's safe to assume that giving up on "Lost" might not be a good idea at this point. … an inspired hour of television … It's dangerous, fast, thrilling and elusive. …

Ain’t It Cool says:

… the best episode of “Lost” since its third-season premiere. …

10 p.m. Wednesday. ABC.