Well, that was certainly an episode of Lost all right. A bit of coolness, a little frustrating obfuscation, a whole lot of people not asking the obvious questions, and a healthy dose of WTF?!?!?! So the island is now Schrödinger's cat, eh? Quantum mechanically, both alive and dead, the castaways both saved and stranded.
As a (would be) writer, it seems like a cheap trick to me. When writing a story, I'm often stymied between two equally good ideas of what should happen next. Using this device, you don't have to choose. You can do them both! In his younger days, one of my writing professors in college wrote a novel wherein the main character has to make an important decision and from that moment on, the text splits into two columns, one for each decision. Clever, but would you want to read it?
However, as a fan of goofy sci-fi television, I actually think it's a pretty fun concept and it's certainly thematically-consistent with the rest of the show. Plus it's a situation that cries out for my favorite character Daniel Faraday, who I'm hoping is somehow alive in the new alternate universe (maybe Eloise fled the island immediately after realizing she shot her own son?).
It was great seeing Boone back. I always liked Ian Somerhalder (he's pretty much my chief reason for watching Vampire Diaries). I guess they couldn't convince Maggie Grace to come back, which is a shame because I felt pretty invested in her character arc and relationship with Sayid. Likewise with Michael and Walt, although Walt would have obviously required some re-casting. I didn't really care that much about Charlie's return and the writers seemed to share my lack interest. Hopefully that will change. I liked how they re-introduced Claire, just as long as it doesn't interfere with my plans for Kate to run back to Nathan Fillion (what? he's on the same network, it could happen!).
In other news, I found a Bettie Page photo that I haven't used! Woo hoo!