Just found a glitch in Batman that will save you 4500 credits (5-6 hours of grinding) because you will not have to buy collectible maps, get you 3000 credits early in the game to spend on upgrades, and save you hours of collecting painstaking collectibles including very difficult ones that require precision gliding.
Also I was unable to use the bat vehicle to reach collectibles. I would just keep flying through them. Not sure if it was just me.
The game requires that you collect 30 of each collectible (90 total), but you can use a single collectible of each type to grind it all out very quickly. All you have to do is
1) find a collectible in the game,
2) grab it
3) restart checkpoint
4) repeat the previous steps with the same collectible until you pop the achievement.
You can check your in game tracker to see it go up every time you collect a collectible (press start and then collectibles).
This trick will also allow you to still get the 3000 credit awards (3 awards for 1000 each) for getting all collectibles.
My version of the game was 126.96.36.199 is anyone is interested.