I don't know, I can't remember what the original didn't have! But there's that mysterious crack, which I'm guessing needs that second-to-last upgrade to interact with.
Oh, I remember you from the Kongregate days, densch!
I've published a small guide with hints and solutions for the new secrets: https://lion123.itch.io/slimes-turn/devlog/846312/how-to-get-the-new-secrets
Been a while but yeah I remember those days.
I started my kongregate account in like 2012 and would still play there if kongregate didn t go downhill in2019 or so.
no new games allowed, only their sh't lost crusaders idle game.
and then the "banishment" of flash in 2019/2020 because some script kiddies were afraif of having their savefiles hacked or stolen -.-