you say "The movie itself was fairly entertaining..." So on two counts it wasn't completely forgettable and the "fairly entertaining" one relates to the whole movie.
This is on the second board now, but I keep these posts for possible other uses so I'll just continue with some praise of CapAm1 even though no one may be reading it here!
There are many more things in the movie that I think are memorable.
The period era and the whole ambience surrounding that.
I thought Chris Evans was very good and his basically playing two roles -- the transition from skinny weakling to Captain America was particularly memorable.
The relationship between him and Peggy and how that evolved, including that shot that seemed to appear in so many of the ads and trailers.
That'd be the shot where he emerges from the machine and she's rather impressed and wants to touch.
Later on, the part where she's jealous (another girl had initiated kissing him) and she shoots at him.
Hugo Weaving was memorable as the villain, Tommy Lee Jones as the Colonel -- these are memorable actors in any movie.
But you at least mentioned "fairly entertaining" and the "woman in it that did a nice job". I put it to you and anyone else reading that latter part in particular is telling. It's the one specific thing you mentioned. That woman, along with Steve/Cap played by Evans, was an Ultimate-Romance Potential gold mine in terms of the Captain America franchise.
That 2011 movie was really the first major live-action incarnation of Captain America and would ultimately be seen by tens of millions worldwide. It had the potential to introduce and pursue an even better-than Superman-Lois dynamic. The latter had everything to do with the success of that franchise. Titanic, Avatar, the first Superman movie with Reeve (and the second were it not for the lame amnesia superkiss ending) owed their enormous Top-10-all-time successes in significant part to a superb romance element that moviegoers actually felt. (As opposed to window dressing or sop-type non-romances.)
Instead, Marvel has chosen the sequel to chuck it all out the window on the altar of some obscure crap comic story one-shot (more or less). They're keeping it an uber-secret from the masses who have no idea, but some of whom may get drawn in by the "woman" being in the credits again. So it may help them get their $90M+ OW we'll see. But I still think it will help mark the Marvel Peak that we're probably going through right now.
Avengers soared at the box office but Thor 2 was confined to basically that $20M OW-only bump (over the first $65M OW), with very little extra beyond that. Maybe the CapAm2 OW manages a bit better and Ultron gets Avengers a bump on its OW, but it's probably just inertia and a last gasp in terms of growth potential. They're going too Inside Marvel Fandom and losing more of the broader (but still small as a percentage of the overall population) moviegoing base. IMO!