This is the 1342nd most frequent German word.
zugleich
At the same time; simultaneously.
Here, 'zugleich' is used to indicate that two qualities or attributes apply simultaneously to the subject.
Er ist klug und zugleich bescheiden.
He is intelligent and at the same time modest.
In this case, 'zugleich' connects two characteristics of the task, providing a view of its contrasting aspects.
Die Aufgabe ist schwierig, zugleich ist sie auch spannend.
The task is difficult, at the same time it is also exciting.
'Zugleich' expresses simultaneity of two actions performed by the subject.