It's interesting how engineer/developer levels are so meaningless across organizations. Where I am, somebody who can only do the work assigned to them isn't senior. That's borderline entry level. Doesn't mean they're a bad programmer or only have 3 hours of experience, just isn't at the higher level. Seems where this person works (Google?) that threshold is at staff
"Do the work assigned to them" has multiple levels of abstraction. You could say it's the task level which would be entry level. You could say it's the project level which would be mid level. You could say it's the a service or domain which would be senior. Staff should be tackling org wide and cross-team issues. The amount of scope and clarity needed for a "problem" changes and gets larger in expectation and more terse in explanation the further you go.
It depends on what you mean. There's lots of ways of looking at this, but I'd think of "entry level" as someone who is assigned individual tasks, and maybe needs help or oversight on completing them. Someone senior is assigned a project, or even a problem (and certainly has input on which projects they work on), and can handle the entire process of investigating, proposing, designing, and implementing the solution to that problem, which may involve oversight or tracking of other people.
Staff+ is additionally directly influencing which projects the org is prioritizing.
