Batman: Arkham Asylum Guide - Walkthrough
As you enter you get the Riddle: “There's no closet in the Gardens, so someone is using the roof instead.”
As you move forward a few steps you should get a CS showing you the room ahead – note the bad guy with the collar – makes me wish I had chosen the Sonic Batarang upgrade now...
The thing about this fight is simple – you cannot be seen or detected – or the hostages die. You need to take out the henchmen leader without being detected or setting off any of the collars – so maybe not having the sonic tool is a bonus?
As you exit the CS you are crouched by the wall – so re-enter Detective Mode and watch the nearest thug – when he is looking away move forward to the grate on the floor and open it, dropping down into the duct. Follow the duct to the end, make sure no one is looking directly at you, then exit the duct and move to the far right to the bench there and collect the last Patient Interview tape for Poison Ivy. Once you give that a good listen, turn around and look up – see that zip point there?
When the guard to your left is looking to HIS right, zip up to the ledge and you will find a duct grate. Quietly rip that off the wall and enter the duct, and stop. This is a good place to rest for a second if you need to relax your hands. Now carefully ease out of the duct and move to the left – see the skeleton hanging half out of the wall? Zoom in on that and scan it to solve the Riddle for this area and get the Bio for Killer Moth!
Now look to the NE (your left) and you will see a small area above the guard that is below you that you can glide to and land on – do that – and you will see that this passes through to the area where another guard is patrolling a catwalk. When he turns around drop down and move to the base of the catwalk, and crouch – as long as he is not heading towards you – meaning he is on the outbound leg of his patrol, target the zip point over your head and zip up so you are hanging off of the edge of the catwalk he is patrolling.
You need to shimmy along his platform to the other end where his patrol point stops and he turns to come back. You can be hanging off of the edge when he walks past and as long as you do not move, he will not detect you. Wait for him to pass, shimmy the rest of the way, and drop down on the ledge here where you will find another duct grate to rip off the wall!
Enter the duct and follow it to the end then zip up several ledges and enter a narrow tunnel that puts you at a trap door above the thug in the control room. Wait until he turns his back and then take him out with a silent kill. You are now above all of the other guys, so take them out on your way down and you get the CS of the hostages being secured. Go You!
Don't forget to go back to the Control Room and take out the two Dancing Teeth here for the 10 Teeth Riddle completion – and then head back down – on the way you will note some fingerprints on a sort of metal plate wall that you can open – when you open it you will spot another one of the Gas Bombs – so go ahead and hack it, then hack it, then hack it again to destroy it! Good on ya mate! Another objective done!
Now take two steps south and then turn to your right – where you will see a secret door – or not see it, either way it is there despite it being all dark and spooky. This is the entrance to the Titan Production Facility – and guess who is inside with a pair of thugs? Yes, it is Big J himself!