Icecream is great but not that much help in fight with Corrupted Heart with Defect. You need to set up your shop quickly, get your defense pumping in turn 2, or there will be no tomorrow.
It is also my main problem with this game, which I adore no question about it, but maybe building card decks is not my forte.
Game doesn’t feel this laser fair like my absolute top game of that genre does, that is FTL.
Yes, both game direct you to go for certain build to fight end boss, you need to be prepared in the right way. StS curve feels steeper, harder, more arbitrary. Relics go a long way, from being so so, to nice, to be absolute run changers. In FTL when I reach end boss I 95% really feel like I have all I need to take it down, it is all down to execution.
In StS, I felt more or less the same with Chapter 3 bosses, but Corrupt Heart feels like it is big cliff that suddenly appears right in your face. Ok, your build annihilated Time Keeper? Cool, now one fight, one shop and done rest site and end boss will finish you in 3 rounds.
I don’t feel like coming back to StS now and I still play FTL at least once a month.