Programming concepts/knowledge: I think this is the part where I messed up, while they are not super difficult on coding algorithms interview questions, one of the interviewers seemed a bit picky when it comes to programming/computer science concepts. Though you may know them in practice from your day-to-day it may also be wise to read up on them and know them in a scholarly manner (as though you are about to take a school exam on it).
So... definitely brush up on key concepts regarding: any framework you claim are familiar with, OOP, concurrency, SQL operations, design patterns, system design... can't remember all the questions but you get the idea. Think more breadth than depth here and just know the common concepts regarding those different topics.