Is there an important difference between 'zwykle' and 'zazwyczaj', meaning "usually"? What is a context where you would prefer one or the other?
They're pretty much interchangeable.
It might be only my personal opinion, but I think zazwyczaj is a bit more formal/less informal, but this difference is so small you should not worry about it.
I think "jadam" should also be accepted, interchangably with "jem".
Definitely. Added now.
Why cant i use czasami
„Czasami” means "sometimes".
It was said that it was wrong, but I guess "ja zwykle jem...." is fine as well?
"Ja zwykle jem chleb na śniadanie" is accepted.
Zazwyczaj was not accepted
It is accepted, it should have worked. Perhaps you had a typo somewhere and the algorithm corrected you to the main answer, which uses "zwykle".
Could you also have "Zazwyczaj ja jem chleb na śniadanie"? because it was not accepted.
Maybe it isn't totally incorrect but for me as a native polish speaker It sounds unnatural, unless you want to emphasise that YOU usually eat bread for breakfest but still it does not sound good:) "jem" instead of "ja jem" is enough;)
"I am eating meat for lunch again."
Translation:Znowu jem na obiad mięso.
Is there any reason why the word order is different for this one?
Both word orders should be interchangeable.
Bardzo dziękuję :)