I'm glad it panned out as well, very fun movie and I can't wait to get it in HD. However I was reading an article on the web the other day about the climax and I realized it probably wasn't as risky as it appears. Let's compare guardians of the galaxy to Marvel's last Marvel Cinematic Universe movie that wasn't a "sequel" The Avengers. Spoilers for both movies to follow..
Both movies are about a rag tag group of heroes that have banded together to save the day. But neither movie starts out that way, both movies have the heroes spend a good chunk of the beginning of the movie fighting each other, not the bad guys.
Both groups consist of the "leader" who wants to do the right thing. The leader guy also makes continous dated references re: Earth's past, next there is the angry heavily muscular guy who spends the entire movie with no shirt on and has colorful skin. Then there is the wise cracking "jerk" who loves blowing stuff up and is a bit of a tortured soul. Lastly there is the alien warrior who joins the team and has to battle their adopted sibling who is on the bad guys team.
The main plot of the movie involves an inifity stone in the hands of the bad guy who wants to use it against another planet for domination/destruction of its people. Just before the climax the large muscular guy gets separated doing his own thing before deciding to team up and kickass as a team and not as a group of individuals. The climax of the movie takes place in the air above a major city where numberous faceless bad guys fight the team. The movie ends with one member attempting to sacrifice himself to save the entire planet in question after the bad guy is stopped but is saved at the last minute by another team member(s).
In either case, I can't wait for the sequel bring on 2017!