The amount of collectibles in this game is quite rediculous. You get an achievement for collecting 50%. I've got just over 1000 so far and I don't have that achievement. I'm guessing that one of the secret achievements will be to collect them all. This isn't necessarily difficult. It's just very time consuming and boring, if you do it all at once. Kindly, the locations of the collectibles can be easily found. On your radar, you will see loads of little red dots scattered almost everywhere, provided you haven't collected many. These red dots are collectibles. The hard work is pretty much done, which will save you frustrated times. I bet trying to find the very last one will be fun. One tiny red dot on a map that is like a million times it's size. Maybe more. Sounds fun. The only thing this leaves is perseverance. So far, I know there are more than 2000. Good luck to all that try.