I can't wait for Slay the Spire 2. The original is the best deckbuilding game I've ever played and I think it's safe to say simply one of my favorite games of all time. I have played it across at least four different systems and still jump into a game now and then. After all, the Playstation was the final platform I took up the game on and I still haven't reached Ascension 20 to complete that platinum trophy. Stupidly, I focused on the Silent and am really hitting a wall around levels 17 and 18. I've got time though, because even though Mega Crit announced the coming sequel a few months back, there aren't any plans for it to release this year.
In a recent newsletter on Steam, the developers did expound on details about the coming sequel and even some reasons why it had to be a sequel in the first place rather than an extension of the original. As for the details the devs "have high confidence that we'll be entering Early Access with a PC, MacOS, and Steam Deck(tm) compatible build." And as for the reasons, orignal dev Casey Yano basically explains that pushing out the first was under such a time and resource crunch that the codebase is riddled with all the things they commented out and patched over. Starting afresh should really give the new iteration a solid foundation to be more performant, expand on more difficult themes and new ideas they want to try, and be able to expand into more platforms.
I'm happy to wait on Slay the Spire 2 so that it will be the best it can be whenever that 2025 Early Access get's nailed down. The Steam page for the game is probably the easiest way to keep up to date on details of when that will eventually be.