Story Teller 10
Have 12 murderous dates with Calendar Man
To get this early you can do it offline. If you want to get an online time stamp for the achievement then you will have to connect to XBL as soon as you engage conversation with him on the last date or do all of them except the one that is closest to the current date and then complete it on that date.
Calendar Man is found in the basement of the Courthouse and can be visited at the beginning of the game. Speak to Calendar Man on each of the following dates that can be found on the calendar in his cell. You must exit the building in order for the achievement progress to save. If done correctly you will notice the next time you speak to him the date is scribbled off the calender. It will take approximately 30 minutes to complete if you do it offline and simply change your console's clock to each of the following dates:
10/31/2011 - Halloween
11/24/2011 - Thanksgiving
12/25/2011 - Christmas
1/1/2012 - New Years Day
2/14/2012 - Valentines Day
3/17/2012 - St. Patrick's Day
4/1/2012 - April Fools
5/13/2012 - Mothers Day
6/17/2012 - Fathers Day
7/4/2012 - Independence Day
8/16/2012 - Feast Day of St. Roch
9/3/2012 - Labor Day
Dates are subject to change according to the year.
Combat, Challenges and Miscellaneous
Pay Your Respects 5
A moment of remembrance
In Crime Alley next to Finnigan's Bar, press near the chalk outlines of your parents. Wait for over one minute until the achievement unlocks. If you move before it unlocks, you will need to start over. The spot you're looking for is at the Custom Waypoint in the image below, or follow the video.
Gotham Base Jumper 5
Jump off the tallest building in Arkham City and glide for 1 minute without touching the ground
You must climb the Wonder Tower during the main story, but you can return post-game to do this as well. Climb on top of the Wonder Tower, jump off and glide around for one minute. Power Grappling does not stop the glide, but you can simply hit the edge of the Restricted Zone to be turned around and push back up in the air to glide indefinitely.
Find someone to play remote Batarang catch with
You must throw the remote Batarang at the Mystery Watcher that you encounter multiple times in the game. This can be missed the first time through however it can still be done in New Game+ right from the start since you have all the gadgets. If you miss it both times then a new save will be required thus classifying this achievement as missable.
You can see the Catch achievement in the first 30 seconds of the Mystery Stalker video.
See "Mystery Stalker" for more details.
Non-existent in the PC version.
50x Combo 5
Complete a combo of 50 moves (any play mode, any character)
This achievement can be done at many different times throughout the game but is easiest done during a sequence like the one in the video below. It is best to get the FreeFlow Focus Combat upgrade to increase movement speed and reaction times as well as the Critical Strikes upgrade that increases the combo by x2 for each successful hit.
Non-existent in the PC version.
Gadget Attack 5
Use 5 different Quickfire gadgets in one fight (any play mode)
You unlock the last combat gadget about 75% of the way through the game. Once you have all the gadgets you must use all of them during one encounter. It does not have to be in the same combo but it does need to hit an enemy.
Batarang (tap )
Bat Gel (+, + again to detonate)
Electrical charge (+)
Freeze blast (,)
Flawless Freeflow Fighter 2.0 5
Complete one combat challenge without taking damage (any character)
This is relatively easy, though if you are having trouble just keep tapping , to jump over enemies without getting hit. Remember to counter often and use special takedowns to remove enemies completely. The first challenge is likely the easiest to do this on.