Great update! I'd say the demo is looking polished and a great advert for the game. I really like the mixing of the deck order - the seagull is a good boss, but knowing it's the final one every time makes it easy to beat with certain decks (reflection wrecks it pretty fast, but has more trouble with other creatures and bosses).
If I could make a suggestion: adding some hint of a larger story/mystery to the intro and ending of the demo seems to be a common way to hook players to buy the full game. The only thing missing from the current demo is a sense of "wait, where's the rest? What happens next?"