To get the "Icarus" and "So Above It All" achievements, you must have access to the Empire State Building, which is the tallest building in the game. It is on Manhattan Island, inside the Red Zone, which you will not have access to until later in the game. Go to the 678, 258 coordinates on your map, and wall run to the top of the building. You should get the "Icarus" achievement before reaching the very top of the building. To get the "So Above It All" achievement, you must have the Movement skill upgraded to the max. You will also need the Jumpy, Dashing, and Jet Propulsion mutations. The Whip-Fist and Extra Dashing mutation are helpful but not required. Run as far as possible up the Empire State Building, then use a fully-charged jump, and immediately begin holding [Glide]. Make sure to save your air-dashes. Pump [Glide] to gain a few extra seconds of hang-time. Once you start to lose forward momentum and start falling, use the air-dash to regain your glide, and repeat the process. Make sure to keep using your remaining air-dashes to stall your fall. You can also use the Whip-Fist attack to pause in mid-air for a few extra seconds.