First, I’ll define critical in terms of programming language features/libraries: anything I can’t reasonably write software without. A lot of things I would call very beneficial, but very few things I would consider critical.
I would consider language features like some kind of parallelism to be very beneficial, but not critical. It’s definitely less pleasant in a language like C to manage threads via an API, but there’s always examples you can follow, you’re not in a vacuum. The only things I would call critical in a language are stuff every general purpose language has anyway, such as control flow statements and grouping functions together (such as classes, modules, namespaces).
Source: Web Dev