The description is a little misleading. Not only will you have to find every upgrade and every detective case clue, you'll also have to aquire every Bat Suit piece, 3 of which are only attainable depending on how you play the game. There are 3 main bosses in the game, and you'll have to play through the game a minimum of 3 times, each time saving a different boss for last. I would recommend saving Penguin for last on your first playthrough, and assuming you've collected all the bat Suit pieces available to that point, you'll unlock the Blackest Night suit, which makes you impervious to damage. The last piece is obtained in The Arkham Wing shortly before the final boss is revealed. Saving Penguin for last will net you the New 52 suit, defeating Joker last will grant the Red Son suit, and Black Mask's path will bring One Million Suit goodness your way. All detective cases and suit pieces carry over from one playthrough to the next, but upgrades, sadly, do not, so you'll have to search those out again each time. You can, however, save the detective cases for your third playthrough if you like, since you have to play through 3 times anyway. It's a bit tedious, especially since the map is such a pain (a top-down map for a side-scrolling game? Really, Armature??) But, once you have them, the satisfaction of those last few trophies popping is ectasy.