Hearthpwn

• Split Personality reads like a Secret, but isn't labeled as one. It's weird to have a lasting aura like that.
• I really like Parlov's Pup. That's an interesting effect for a Beast.
• Regarding Sweet Dream, there aren't many spells in the game that rely on a specific board/hand/deck state to function on a basic level. They generally provide something if played sub-optimally, in case they are generated from an outside source. To My Side!, for example, at least gives you one Animal Companion if you fail to meet the deck conditions. With all that in mind, I'm wondering if something like "Discover a Dream card. If you're holding a Dragon, Discover another one." would be preferable.
• Bride of C'Thun is freaky and I don't want to think about the flavor, however the effect is neat and I like the card a lot. I didn't think connecting the Lich to C'Thun made sense to me, but I do have a soft spot for the Old God.

I'm more-or-less fine with everything else, although there are a couple of small mistakes in some of your cards:

1. Untamed Egghatcher should say "Dragon Eggs"
2. Gnomish Satellite should say "After this attacks and kills a minon"
3. Prophet Al'Zatar should say "every card with a random effect"
4. Spirit of the Sky Serpent should not say "minions", and needs a period.
5. Not a typo, but Quetz'lun could say "hand and board" to save space. See: Hir'eek, the Bat.

Do you like the explanation outside of the set's spoiler box? I couldn't decide which one is better: everything in the spoiler makes it cleaner, but also makes the post look empty.