Oh look! Isn't it too early? Maybe. I already watched this video on youtube so I think it's the best to write the review now. Spoilers are strong in this one. Let's begin, shall we?
Twilight is still studing about the chest. It's okay, I guess but if all episodes are centered around it, that won't be too cool. And returning to the castle already? I would wait a little more time...
Rainbow and Applejack are rivals again. You can't be more daring than Daring Do, silly! Don't even try going to the old castle again...ah nevermind. Rarity and Fluttershy are going there too (oh my god, this will be interesting). They don't even know about each other, till the end of the episode.
The rest of this episode is basically a horror movie without scary things and gore. I'm not used to this. Plus, this episode really needs a song... some music from Luigi's mansion Dark moon with some pony lyrics... THAT would be awesome. However, the millions of trapdoors and stuff were okay. Predictable but okay.
And we end this episode with NO info about the keys, and the mane 6 begins to write a...diary??? Oh boy, I don't think this will be too exciting. At least we know who is the Shadow pony. Or did we?