You think you made a good first impression and the acting manager thinks not so good? Do you agree on any "good" parts? Those would be things to continue for sure. A good manager will gently advise an employee of things they need to do so they perform well and do the best work they can. A good manager will help the employee do those things.
I'm curious about the term "acting manager" - is this person there only temporarily until a full term manager is hired or comes back? An "acting manager" might not have all the expertise a long term manager with experience has. Or if they wanted to be made full time manager, they could be "acting tough", or maybe they think that's what they're supposed to be like, or maybe you're a star and it made them nervous that you could outdo them in the long run. Anyhow, my point is that when someone is an "acting" anything and is spewing criticism, I wonder about them and their motivations. It's quite possibly not about you at all.
The very fact that you're concerned about this suggests to me that you are a willing worker who wants to do your best. I'd think that's a good first impression. I'd want you on my team! Just my take on things.