Batman: Return to Arkham - Arkham Asylum

Relatively straight forward, basically you need to do everything in one counter.

Punch - X
Counter - Y
Ground take down - Right Trigger + Y
Batterang - Left Trigger
Stun - B
Throw Enemy - A + X
Enemy takedown Y+B
Grapple Hook - Right Trigger 2 times
Jump over Enemy - A+A

it takes time, I had to take a good amount of time to re get use to the original controls but very doable

In order to unlock this achievement you must perform a single freeflow in which all variations of moves are completed in one combo.

This is extremely challenging and took me a while to master on the 360 version/

Challenges are perfect as you can restart if you mess up. 1st Wave of Sewer Bat Extreme Challenge is a great location to practice.

You must have purchased these upgrades:

Special Combo Throw, Combo Batarang, Combo Takedown Critical Combo Strikes, & Unlocked Batclaw

Sequence
1) Counter
2) Strike
3) Vault
4) Cape Stun
5) Combo Batarang
(Counter)
6) Ground Takedown
7) Throw
(Strike x2)
8) Combo Takedown
9) Batclaw

The above sequence is not set in stone but a variation of all of the moves above must be completed in one single uninterrupted combo.

I recommend watching a video. It really helps you understand how to complete this.
Here is one by Achievement Hunter it helped me on the original game.

https://www.youtube.com/watch?time_continue=13&v=8mFBYBW...

Here is a link to the original games trueachievement page with lots of various solutions

The above solutions are great, I just have another tip for people who have finished the game but still need this achievement. Outside the combat challenges this is the fastest way I have found.

Start a new game on Easy, because you level up fastest on Easy. Proceed as usual, and along the way try to nab all the Riddler Trophies, Patient Interviews, Chronicle scans, Riddles solved, and Joker Teeth as you go, as they give you a lot of XP. Don't bother backtracking just grab what is obvious. You can also use this excellent guide which presents the items by area in the order which they are attainable:
https://www.gamesradar.com/batman-arkham-asylum-riddler-guid...

Progress to the point you have gotten your Batclaw, and you are directed to Arkham Mansion. As the above solution states, you must have the following leveled up by this time: Special Combo Throw, Special Combo Takedown, Special Combo Boost, Combo Batarang, and Special Combo Strikes. If you haven't leveled enough to have all these, go back and find some more Riddler Secrets until you do.

Go into Arkham Mansion and you end up high above a big group of criminals, drop down and make your attempt to get the perfect combo, using all possible moves. This is the earliest spot in the main game because you needed the Batclaw, and they are all standard enemies without knives or stun batons. There are enough criminals that if you lose your streak once or twice, you still have a good chance of success before you knock them all out. If it looks like you aren't going to get it this round, pause and Restart From Checkpoint, which puts you right back above the criminals for a really quick reset.

The order you perform the required moves may vary, but what I recommend is to attempt the normal Ground Takedown ( + ) as early as possible, as soon as you have an enemy separated from the rest enough to pounce on before getting interrupted. This is the move most likely to fail so it's better to learn that early in your current attempt so you can reset. I also recommend doing the Combo Batclaw (tap twice) LAST in your chain, as it leaves you terribly vulnerable otherwise.

It still takes a lot of practice. To help commit the moves to muscle memory, from the beginning of the game every time you fight a group of enemies you should be attempting to include all the moves you have available up to that point. Try to do a combo adding one new move in each attempt until you have that sequence down, then add another until that becomes automatic, and so on.

You too can get this achievement, I believe in you! Some of these methods may not work with your playstyle, and you may have found an even better spot in the main story to get this. Please comment below with any additional tips or questions you may have. Good gaming!