Well, I said I'd be content if I was entertained (I was) and felt like it was the same old Henry "Indiana" Jones (and I did). There are many moments where I felt like I was right back in my childhood with an old friend, whips cracking and cars chasing and explosions...uh...exploding.

It's when it tried to make statements about the period (late 50s instead of the pre-WWII era) that I think it fell flat, and at times when it tried to explain (and show) the source of the crystaline cranium referenced in the title. But even so, those moments made sense and didn't make the movie bad, just...different. Without going into too much detail, Indy has always chased mythical and
mystical artifacts (Ark of the Covenant, Sankara Stones, Holy Grail), so I guess the artifact and all they chose for this film was the next natural step, especially considering the time period. All the same, it gave it a very different feeling.
But it's still Indiana Jones, and I still had a good time, and it still felt familiar. Let me put it this way....
I grew up on the original
Star Wars and
Indiana Jones trilogies. The newer
Star Wars trilogy that was released within the last few years were good movies in their own right, but I still seperate them in my mind from the originals.
Indiana Jones and the Kingdom of the Crystal Skull, however, I am still able to connect to the originals in my head. It's just one more adventure with the same old Indy. Does that make any sense?
In short: I'd recommend seeing it. Keep your mind open and don't expect it to be bad or good, and you should be left feeling like you had some good, clean fun with an old(er) friend.