Joss Whedon totally sticks the landing. I literally cannot think of one complaint about this movie (if we forget about the 3D downconversion).
Actually, wait, I do have one. If you're going to have Harry Dean Stanton make a cameo in a movie called The Avengers, it should have been for a scene like this:
Current Soundtrack: Nas, "Daugthers" and "The Don"