You need level 32 characters to be able to complete Crota’s End Hard Mode.
Traverse the Abyss Crota’s End Raid Hard Mode The Dark Below
This information for Crota’s End Hard Mode is on top of the standard mode guide:
http://auluftwaffles.com/2014/12/09/traverse-the-abyss-crotas-end-raid-the-dark-below-destiny/
Weight of will only go up to 10 but it ticks up faster. Hallowed Thralls can spawn and more Thralls will spawn. The maze is the same in terms of layout, please see this page for a map that also shows chest locations:
http://auluftwaffles.com/2014/12/10/chest-locations-crotas-end-raid-in-the-dark-below-in-destiny/
The lamps last shorter so you need to be faster going through The Abyss. Most people are calling 2 materials from the first chest, so only single loot for the first chest.
At the end of The Abyss when activating the bridge get a hunter to activate the light circle and then hide behind the pillars. Keep switching sides and go into stealth and run across the bridge as soon as you can.