That was fun. Agreed this seems more for the hardcore Marvel fan as it had a comic book feel with a lot of references.
I really liked the fast pace and telling a story in 30 minutes that was originally 2 hours without hurting any of the emotional pay offs. They also made good use of the animation having both an air force battle and giant tentacle monster in the same episode, something that wouldn't have been practical with live action. Nice to hear Hayley Atwell and Sebastian Stan but interesting they couldn't get Chris Evans.
To answer the question What if... Captain Carter were the first Avenger?: