Batman: Arkham Origins

The achievement unlocks when Batman returns to the Batcave after investigating the prison and uses the computer to search for some of Killer Croc's claims pertaining to the Black Mask.

It's a story related achievement and is therefore unmissable. I've heard the groans about doing Croc's fight already, so I figured I would post a few tips in the hope they can help others:

-Croc can only be injured in combat by stunning him him and then performing a beat down. Remember to evade often and carefully to ensure Croc does not get his hands on you.
-Also remember to double tap LT when he is holding the propane canisters to deliver substantial damage to Croc.

After the first group of enemies drops in continue to focus on killing Croc and simply stunning and evading the mobsters. The reason I suggest this two fold.
--Croc will damage the mobsters enough for the fight, and when you evade one of his attacks that either staggers or moves the mobsters this will provide you with the perfect moment to stun/beat down.
--The second reason is that when the second helicopter drops in, it will only drop off enough mobsters to equal a total of 3. So if both of your boys are still alive you'll only have to content with an additional mobster in the mix, and when simply stunning and moving onto Croc, this makes things easier.

Now these tips may not be of any help, but on hard difficulty I was looking for the smallest things to give me the edge over Croc, and this is admittedly where I spent the majority of this first part of the game.