Did you have to complete 100% game completion to get the end credits? I remember completing all the missions and getting to the end credits, but don't remember if I completed 100% of the game. I think I may have missed one of the rampages, but I do remember getting to the end credits.
I got to the end credits and I didn't complete the game 100%, so I guess you will still be able to view the game credits as long as you completed the missions.
You don't need to get 100% completion to get the end credits, I think I was around 85% when I got them, so yeah..
There is no need to complete everything if you want to see the end credits; as long as every mission has been completed, you will definitely see them. If I recall, there's a bonus for getting a perfect rate of 100%.
