The Retain keyword is similar to the effects from Treasury or Mandarin in Dominion, where you put some card(s) back on top of your deck during clean up if you meet the condition. Treasury especially is also a cantrip, so it doesn't use up space in your hand on the next turn.
Innate of course doesn't have a precedent in Dominion, since you don't keep your deck around between games. Ethereal could - there's no technical reason you couldn't print a Dominion card with text like, "During clean up, trash this card if you would discard it from your hand". I don't think there are any such cards, and I suspect they'd be generally worse in Dominion than Ethereal is in StS. Actually, having a deck of cards using in junking attacks with that text separate from ruins and curses might be interesting - curses that trash themselves, so you could hand them out a lot more aggressively without destabilizing the entire game.
Dominion's traveler cards were Donald X's attempt to make cards that change during the game, though of course Slay the Spire can push that idea much further.
Artifacts and States are a little bit like the Watcher's stances, but less deck-defining. You generally don't build a deck around having a particular artifact or state, but you can use them to get a little extra juice.
I agree, limiting your plays each turn (either with mana or dominion's limited actions) does a lot to change the texture of a game. The Ascension family of deckbuilders where you can just slam your whole hand down every turn tend to leave me underwhelmed.
I don't mean to rag on StS for being unoriginal, quite the opposite, it's great.
Yes, the fact that you can send email to people who aren't using your email system is the main thing that's keeping chat services stuck as part of a company's communication tools and not being the entire (or almost entire) thing.
I actually wrote the easy 50% of email back compatibility for a chat app once - it wasn't as hairy as I expected it was going to be. Everyone has a unique username (or at least username+org pair) so use that to generate an email address for them. Similarly, generate an email address for every group/room. When you receive an email for one of those addresses, use the from headers to find/create a new pseudo-user and dump the body of the email in as a chat message. When someone writes in chat that has a pseudo-user as one of the people watching that chat, send them an email with that text and throw in a few previous messages as a fake reply chain for context.
There are a lot of hairy details about thread management and making sure you don't send pseudo-users too many emails and dealing with all the messed up headers that different platforms send you and trying to only extract the actual message and not the signature/replies from an email and attachments so on that I only worked on a little before the whole thing was shuttered. But it was really cool. Email users tended not to notice that anything was different (they're used to email looking weird from various services) and chat users got to stay in chat that was a little awkward instead of having to switch to a different tool entirely to talk to people outside the organisation. (And, if all the different chat services started doing it, you'd get really janky chat federation for free!) And it lets you get a lot of stuff that gets made as Slack integrations for free, too. Why bother setting up a bot to post to chat when a Jenkins build fails when you can just give Jenkins your dev chat's email address and let it send emails?
I don't know if it's really that rare, though. From where I sit Maciej is playing the fox/anansi/trickster character to a tee, with a healthy dose of ha ha only serious (http://www.catb.org/~esr/jargon/html/H/ha-ha-only-serious.ht...). Whether it's a character he's pretending to be or just his natural communication style is for him to say, but dude-who-wanders-in-to-fuck-up-your-ego-with-practical-jokes is a pretty well-established archetype that predates "troll".
I don't get the logic that starts with "Technology is moving fast but email doesn't change" and leads to the solution being papering over email's faults with some slick UI. It's like the whole city's water pressure is failing and everyone is complaining about faucet design instead of that we're using two thousand year old aqueducts. We need more out of online communication than email can give us at a really fundamental level. Suffice to say, my thoughts on this are longer than an HN comment: http://structur.al/articles/after-email/
Innate of course doesn't have a precedent in Dominion, since you don't keep your deck around between games. Ethereal could - there's no technical reason you couldn't print a Dominion card with text like, "During clean up, trash this card if you would discard it from your hand". I don't think there are any such cards, and I suspect they'd be generally worse in Dominion than Ethereal is in StS. Actually, having a deck of cards using in junking attacks with that text separate from ruins and curses might be interesting - curses that trash themselves, so you could hand them out a lot more aggressively without destabilizing the entire game.
Dominion's traveler cards were Donald X's attempt to make cards that change during the game, though of course Slay the Spire can push that idea much further.
Artifacts and States are a little bit like the Watcher's stances, but less deck-defining. You generally don't build a deck around having a particular artifact or state, but you can use them to get a little extra juice.
I agree, limiting your plays each turn (either with mana or dominion's limited actions) does a lot to change the texture of a game. The Ascension family of deckbuilders where you can just slam your whole hand down every turn tend to leave me underwhelmed.
I don't mean to rag on StS for being unoriginal, quite the opposite, it's great.